| 0/0 |
2026/08/30 00:37 |
flow |
assessment-security |
42m
Results: map[DenialOfService:false Explanation:**Analysis of the Bug**
The bug report indicates a `WARNING` in `__kvmalloc_node_noprof` at
`mm/slub.c:6908`. This warning is triggered when the kernel attempts to allocate
a memory block larger than `INT_MAX` (2GB) without the `__GFP_NOWARN` flag.
Looking at the call trace, the warning originates from `create_strip_zones` in
`drivers/md/raid0.c`. The vulnerable code attempts to allocate the `devlist`
array using `kvzalloc`:
```c
conf->devlist = kvzalloc(array3_size(sizeof(struct md_rdev *),
conf->nr_strip_zones,
mddev->raid_disks),
GFP_KERNEL);
```
The size of the allocation is calculated using `array3_size`, which multiplies
the three arguments. If `mddev->raid_disks` is extremely large, the
multiplication can exceed `INT_MAX` or overflow to `SIZE_MAX`. When this huge
size is passed to `kvzalloc` (which uses `GFP_KERNEL` and lacks `__GFP_NOWARN`),
the memory allocator explicitly catches the "crazy size", triggers a
`WARN_ON_ONCE`, and safely returns `NULL`.
**Security Impact Assessment**
1. **Exploitable:** **No.** The kernel correctly identifies the oversized
allocation request, issues a warning, and returns `NULL`. The `NULL` return is
properly checked by `create_strip_zones`, which aborts the array assembly and
returns `-ENOMEM`. There is no memory corruption, out-of-bounds access, or
information leak.
2. **Denial of Service (DoS):** **No.** The warning does not halt the system
(unless `panic_on_warn` is enabled, which is not the default in production).
Because the allocation is aborted before any memory is actually consumed, it
does not cause memory exhaustion or OOM conditions. The system continues to
operate normally.
3. **Accessible From Unprivileged Processes / User Namespaces:** **No.**
Configuring and running an md array via `md_ioctl` (e.g., `SET_ARRAY_INFO`,
`RUN_ARRAY`) or sysfs requires `CAP_SYS_ADMIN` in the initial user namespace
(enforced via `capable(CAP_SYS_ADMIN)`). Unprivileged users or users inside a
user namespace cannot reach this code path.
4. **Peripheral Trigger:** **Yes.** A malicious USB device presenting a crafted
md superblock with an artificially huge `raid_disks` value could trigger this
bug. If the system auto-assembles RAID arrays (either via the kernel's boot-time
`md_autodetect_dev` or via userspace udev rules invoking `mdadm`), the crafted
superblock will be parsed and passed to the kernel, triggering the warning.
5. **Other Triggers:** The bug is isolated to the MD (Software RAID) subsystem
and block device layer. It cannot be triggered via network traffic, malicious
filesystems (as it operates at the block layer, not the VFS layer), or from a
typical KVM guest/host context. Exploitable:false FilesystemTrigger:false NetworkTrigger:false PeripheralTrigger:true RemoteTrigger:false Unprivileged:false UserNamespace:false VMGuestTrigger:false VMHostTrigger:false]
|
| 1/1 |
2026/08/30 00:37 |
action |
syz-repro-to-c-repro |
0m
Results:
|
| 2/1 |
2026/08/30 00:37 |
action |
kernel-checkouter |
0m
Results: map[KernelSrc:/app/workdir/cache/src/d3e5e845ea1e86991b96377ebe5c58374353a72c]
|
| 3/1 |
2026/08/30 00:37 |
action |
kernel-builder |
18m
Results: map[KernelObj:/app/workdir/cache/build/9b090ba62275329d4cf23f0f7587dae755e54fdf]
|
| 4/1 |
2026/08/30 00:56 |
action |
codesearch-prepare |
18m
Results: map[Index:codesearch-index]
|
| 5/1 |
2026/08/30 01:14 |
agent |
expert |
5m
Model:
Results: map[DenialOfService:false Exploitable:false FilesystemTrigger:false NetworkTrigger:false PeripheralTrigger:true RemoteTrigger:false Unprivileged:false UserNamespace:false VMGuestTrigger:false VMHostTrigger:false]
Instruction: You are an experienced Linux kernel security engineer. Your task is to analyze given kernel bug report
and determine its security impact based on the following dimensions.
Use the provided tools to examine the source code, check for capability checks (e.g., capable(), ns_capable()),
and understand the nature of the bug. Analyze the given kernel build and configuration.
You can check the kernel config by grepping ".config" file; you can check kernel cmdline by grepping
".config" file for "CONFIG_CMDLINE=". Assume sysctl parameters have default values.
But analyze for the corresponding production build w/o debugging tools enabled (like KASAN, KMSAN, UBSAN).
Try different strategies when analyzing the bug:
- think of ways in which the vulnerable code is unreachable
- or the other way around: try to come up with different ideas of how an unprivileged user can reach the bug
If still unsure err on the side of the bug being non-exploitable/not-accessible.
In the final reply, provide a reasoning for your assessment.
Analysis dimensions:
* Exploitable:
Determine if the bug can result in memory corruption, elevated privileges, or an information leak.
Memory safety issues are almost always exploitable (KASAN or UBSAN reports for use-after-free, out-of-bounds;
refcounting issues, corrupted lists, etc). When kernel is crashing on a completely wild pointer access
(e.g. user-space address, or non-canonical address, but not on NULL or address corresponding to KASAN shadow
for NULL address), including both data accesses and control transfers, that also usually implies possibility
of exploitation. Such reports usually say "unable to handle kernel paging request".
Uses of uninitialized values detected by KMSAN may be exploitable b/c attacker frequently can affect uninit
values with spraying techniques. However, for these exploitability depends on how exactly the uninit value
is used in the code, and what it affects.
Information leaks are exploitable on their own and should be classified as such. A bug that copies kernel
memory contents to userspace (e.g. an out-of-bounds read whose result is returned to the caller, or
uninitialized stack/heap bytes written to a user buffer) is exploitable: it can reveal kernel pointer
values and defeat KASLR, expose sensitive data such as cryptographic keys or other processes' memory, and
serves as a necessary building block in most modern kernel privilege-escalation exploit chains. Do not classify
an information leak as non-exploitable solely because it does not directly cause a memory write or control-flow
hijack; the leak itself is the exploit primitive.
Think of what happens after the bug is triggered. Some bugs cause kernel panic and halt execution,
they are harder to exploit. For example, BUG reports halts the kernel. However, WARNING reports don't halt
execution in production builds. Debug bug detection tools (like KASAN, KMSAN, KCSAN, UBSAN) are also not enabled
in production builds, so attacker can freely exploit these bugs w/o being detected by these tools.
If you see an integer overflow, think how the overflowed value used later (if it's used as allocation size,
or an array index). If you see an out-of-bounds read, think if it's followed by an out-of-bounds write as well.
Some KCSAN data-races may be exploitable by skilled attackers as well. Think what data structures got corrupted
as the result of data races and how. However, note that kernel has lots of "benign" data races that don't lead
to any runtime misbehavior at all.
* Denial Of Service:
Determine if the bug can result in denial-of-service. Most bugs can, since they cause system crash,
hangs, deadlocks, or resource leaks. This is mostly applicable to WARNING bugs that won't cause system crash
in production. For these think what will be consequences of the violation of the kernel assumptions flagged
by the WARNING. In some cases the unexpected condition is also properly handled by the normal control flow
(e.g. with "if (WARN_ON(...))"), these won't cause denial-of-service. If the condition is not handled,
then it may or may not cause denial-of-service.
* Accessible From Unprivileged Processes:
Determine if the bug can be reached from a typical (non-root) user process that does NOT have any special capabilities
(like CAP_SYS_ADMIN, CAP_NET_ADMIN, CAP_NET_RAW, CAP_PERFMON) or access to device nodes restricted to root.
Assume that unprivileged_bpf_disabled=1, that is eBPF loading is not accessible. However, cBPF (classical BPF)
is still accessible to non-root processes.
Assume that user namespaces are not accessible, that is, the process cannot get the mentioned capabilities even
within a new user namespace (checked by ns_capable() function in the kernel sources).
* Accessible From User Namespaces:
Determine if the bug can be reached within a user-namespace where the process has all capabilities
(including CAP_SYS_ADMIN, CAP_NET_ADMIN, CAP_NET_RAW, CAP_PERFMON). Such capabilities are checked with ns_capable()
function in the kernel sources.
* VM Guest Trigger:
Determine if the bug can be triggered from the context of a typical KVM guest (e.g., set up by a QEMU VMM).
Consider accesses to standard Linux host paravirtualized features (virtio-blk, virtio-net, etc.),
and handling of VM exits in the KVM code.
* VM Host Trigger in The Confidential Computing Context:
Determine if the bug can be triggered in a confidential computing guest kernel from the context of a KVM host.
Consider access to standard Linux guest paravirtualized features (virtio-blk, virtio-net, etc.).
* Ethernet Network Trigger:
Determine if the bug can be triggered by processing ingress network Ethernet traffic, either directly (network stack)
or via drivers exposed to network data.
* Other Remote Trigger:
Determine if the bug can be triggered by processing remote traffic other than Ethernet (Wifi, Bluetooth, NFC, etc).
* Peripheral Trigger:
Determine if the bug can be triggered via an untrusted peripheral device that can be physically plugged
into a system, such as a USB device or a niche hardware driver handling external hardware inputs.
This is particularly important for mobile and desktop environments where users can plug in unknown devices.
* Malicious Filesystem Trigger:
Determine if the bug can be triggered by the kernel mounting and parsing a malicious filesystem image.
This is highly critical for Desktop and Mobile environments where external media or downloaded images
might be auto-mounted.
Don't make assumptions about the kernel source code (it may be different from what you assume it is).
Extensively use the provided code access tools (codesearch-*, git-*, grepper, etc)
to examine the actual source code, and confirm any assumptions.
Prefer calling several tools at the same time to save round-trips.
Use set-results tool to provide results of the analysis.
It must be called exactly once before the final reply.
Ignore results of this tool.
Prompt:
The kernel bug report is:
loop0: detected capacity change from 0 to 32768
xfs: Deprecated parameter 'noattr2'
XFS: noattr2 mount option is deprecated.
XFS (loop0): Mounting V5 Filesystem bfdc47fc-10d8-4eed-a562-11a831b3f791
XFS (loop0): Ending clean mount
XFS (loop0): Quotacheck needed: Please wait.
XFS (loop0): Quotacheck: Done.
md: async del_gendisk mode will be removed in future, please upgrade to mdadm-4.5+
md0: Warning: Device ram1 is misaligned
------------[ cut here ]------------
!(flags & __GFP_NOWARN)
WARNING: mm/slub.c:6908 at __kvmalloc_node_noprof+0x7de/0x870 mm/slub.c:6908, CPU#0: syz.0.0/5312
Modules linked in:
CPU: 0 UID: 0 PID: 5312 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:__kvmalloc_node_noprof+0x7de/0x870 mm/slub.c:6908
Code: ff 48 c7 c7 b0 5c e9 8e 48 89 de e8 5c eb ea 02 e9 fd fb ff ff 48 c7 c7 f0 5c e9 8e 48 89 de e8 48 eb ea 02 e9 32 fc ff ff 90 <0f> 0b 90 45 31 f6 e9 ef fd ff ff 90 0f 0b 90 e9 46 ff ff ff 49 83
RSP: 0018:ffffc9000ee9f550 EFLAGS: 00010246
RAX: 00000001ffffffff RBX: 00000000000029c0 RCX: 8000000000000001
RDX: ffffffffffffffff RSI: ffffffff8c6d1560 RDI: ffffffff8c6d1520
RBP: ffffffffffffffff R08: 00000000000029c0 R09: 00000000ffffffff
R10: 0000000000000006 R11: 0000000000000002 R12: 00000000ffffffff
R13: ffffffff887a930f R14: 0000000000000000 R15: 0000000000000200
FS: 00007f8f049f86c0(0000) GS:ffff88808c30a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f70c37ede9c CR3: 0000000042c8f000 CR4: 0000000000352ef0
Call Trace:
<TASK>
create_strip_zones+0xb6f/0x2170 drivers/md/raid0.c:150
raid0_run+0x3de/0xed0 drivers/md/raid0.c:424
md_run+0xc3d/0x1cd0 drivers/md/md.c:6779
do_md_run+0x35/0x720 drivers/md/md.c:6880
md_ioctl+0x1e2b/0x2610 drivers/md/md.c:8515
blkdev_ioctl+0x5e3/0x740 block/ioctl.c:798
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8f03b9e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8f049f7fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f8f03e25fa0 RCX: 00007f8f03b9e159
RDX: 0000000000000000 RSI: 00000000400c0930 RDI: 000000000000000a
RBP: 00007f8f03c35024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8f03e26038 R14: 00007f8f03e25fa0 R15: 00007ffdcdc958c8
</TASK>
Reply: **Analysis of the Bug**
The bug report indicates a `WARNING` in `__kvmalloc_node_noprof` at `mm/slub.c:6908`. This warning is triggered when the kernel attempts to allocate a memory block larger than `INT_MAX` (2GB) without the `__GFP_NOWARN` flag.
Looking at the call trace, the warning originates from `create_strip_zones` in `drivers/md/raid0.c`. The vulnerable code attempts to allocate the `devlist` array using `kvzalloc`:
```c
conf->devlist = kvzalloc(array3_size(sizeof(struct md_rdev *),
conf->nr_strip_zones,
mddev->raid_disks),
GFP_KERNEL);
```
The size of the allocation is calculated using `array3_size`, which multiplies the three arguments. If `mddev->raid_disks` is extremely large, the multiplication can exceed `INT_MAX` or overflow to `SIZE_MAX`. When this huge size is passed to `kvzalloc` (which uses `GFP_KERNEL` and lacks `__GFP_NOWARN`), the memory allocator explicitly catches the "crazy size", triggers a `WARN_ON_ONCE`, and safely returns `NULL`.
**Security Impact Assessment**
1. **Exploitable:** **No.** The kernel correctly identifies the oversized allocation request, issues a warning, and returns `NULL`. The `NULL` return is properly checked by `create_strip_zones`, which aborts the array assembly and returns `-ENOMEM`. There is no memory corruption, out-of-bounds access, or information leak.
2. **Denial of Service (DoS):** **No.** The warning does not halt the system (unless `panic_on_warn` is enabled, which is not the default in production). Because the allocation is aborted before any memory is actually consumed, it does not cause memory exhaustion or OOM conditions. The system continues to operate normally.
3. **Accessible From Unprivileged Processes / User Namespaces:** **No.** Configuring and running an md array via `md_ioctl` (e.g., `SET_ARRAY_INFO`, `RUN_ARRAY`) or sysfs requires `CAP_SYS_ADMIN` in the initial user namespace (enforced via `capable(CAP_SYS_ADMIN)`). Unprivileged users or users inside a user namespace cannot reach this code path.
4. **Peripheral Trigger:** **Yes.** A malicious USB device presenting a crafted md superblock with an artificially huge `raid_disks` value could trigger this bug. If the system auto-assembles RAID arrays (either via the kernel's boot-time `md_autodetect_dev` or via userspace udev rules invoking `mdadm`), the crafted superblock will be parsed and passed to the kernel, triggering the warning.
5. **Other Triggers:** The bug is isolated to the MD (Software RAID) subsystem and block device layer. It cannot be triggered via network traffic, malicious filesystems (as it operates at the block layer, not the VFS layer), or from a typical KVM guest/host context.
|
| 6/2 |
2026/08/30 01:14 |
llm |
expert |
0m
Model:
Tokens:
input: 7739
output: 37
thoughts: 130
Thoughts: **Investigating a Kernel Warning**
Okay, so I've got a kernel warning, specifically in `__kvmalloc_node_noprof` at `mm/slub.c:6908`. The warning is triggered when `__GFP_NOWARN` isn't set, which immediately tells me something about memory allocation behavior. I need to figure out *why* it's getting triggered in this specific context.
The call trace is key here: `create_strip_zones` calls `raid0_run`, which is called by `md_run`, and so on. This path points to the RAID code, which makes sense, I suppose. It all ends up being driven by an `ioctl` call from user space via the block device.
My next move is clear. I need to dive into `create_strip_zones`, specifically within `drivers/md/raid0.c`. I need to understand what memory allocations it's making and, more importantly, *why* it's not using `__GFP_NOWARN` in those allocations. Something in this function is likely not handling a specific error condition correctly, which is resulting in the warning. It could be a simple oversight, or perhaps something more fundamental about how the striping logic is interacting with the memory allocator. Time to roll up my sleeves and examine that code.
|
| 7/2 |
2026/08/30 01:14 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/md/raid0.c Name:create_strip_zones]
Results: map[SourceCode: 66: static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
67: {
68: int i, c, err;
69: sector_t curr_zone_end, sectors;
70: struct md_rdev *smallest, *rdev1, *rdev2, *rdev, **dev;
71: struct strip_zone *zone;
72: int cnt;
73: struct r0conf *conf = kzalloc_obj(*conf);
74: unsigned int blksize = 512;
75:
76: if (!mddev_is_dm(mddev))
77: blksize = queue_logical_block_size(mddev->gendisk->queue);
78:
79: *private_conf = ERR_PTR(-ENOMEM);
80: if (!conf)
81: return -ENOMEM;
82: rdev_for_each(rdev1, mddev) {
83: pr_debug("md/raid0:%s: looking at %pg\n",
84: mdname(mddev),
85: rdev1->bdev);
86: c = 0;
87:
88: /* round size to chunk_size */
89: sectors = rdev1->sectors;
90: sector_div(sectors, mddev->chunk_sectors);
91: rdev1->sectors = sectors * mddev->chunk_sectors;
92:
93: if (mddev_is_dm(mddev))
94: blksize = max(blksize, queue_logical_block_size(
95: rdev1->bdev->bd_disk->queue));
96:
97: rdev_for_each(rdev2, mddev) {
98: pr_debug("md/raid0:%s: comparing %pg(%llu)"
99: " with %pg(%llu)\n",
100: mdname(mddev),
101: rdev1->bdev,
102: (unsigned long long)rdev1->sectors,
103: rdev2->bdev,
104: (unsigned long long)rdev2->sectors);
105: if (rdev2 == rdev1) {
106: pr_debug("md/raid0:%s: END\n",
107: mdname(mddev));
108: break;
109: }
110: if (rdev2->sectors == rdev1->sectors) {
111: /*
112: * Not unique, don't count it as a new
113: * group
114: */
115: pr_debug("md/raid0:%s: EQUAL\n",
116: mdname(mddev));
117: c = 1;
118: break;
119: }
120: pr_debug("md/raid0:%s: NOT EQUAL\n",
121: mdname(mddev));
122: }
123: if (!c) {
124: pr_debug("md/raid0:%s: ==> UNIQUE\n",
125: mdname(mddev));
126: conf->nr_strip_zones++;
127: pr_debug("md/raid0:%s: %d zones\n",
128: mdname(mddev), conf->nr_strip_zones);
129: }
130: }
131: pr_debug("md/raid0:%s: FINAL %d zones\n",
132: mdname(mddev), conf->nr_strip_zones);
133:
134: /*
135: * now since we have the hard sector sizes, we can make sure
136: * chunk size is a multiple of that sector size
137: */
138: if ((mddev->chunk_sectors << 9) % blksize) {
139: pr_warn("md/raid0:%s: chunk_size of %d not multiple of block size %d\n",
140: mdname(mddev),
141: mddev->chunk_sectors << 9, blksize);
142: err = -EINVAL;
143: goto abort;
144: }
145:
146: err = -ENOMEM;
147: conf->strip_zone = kvzalloc_objs(struct strip_zone, conf->nr_strip_zones);
148: if (!conf->strip_zone)
149: goto abort;
150: conf->devlist = kvzalloc(array3_size(sizeof(struct md_rdev *),
151: conf->nr_strip_zones,
152: mddev->raid_disks),
153: GFP_KERNEL);
154: if (!conf->devlist)
155: goto abort;
156:
157: /* The first zone must contain all devices, so here we check that
158: * there is a proper alignment of slots to devices and find them all
159: */
160: zone = &conf->strip_zone[0];
161: cnt = 0;
162: smallest = NULL;
163: dev = conf->devlist;
164: err = -EINVAL;
165: rdev_for_each(rdev1, mddev) {
166: int j = rdev1->raid_disk;
167:
168: if (mddev->level == 10) {
169: /* taking over a raid10-n2 array */
170: j /= 2;
171: rdev1->new_raid_disk = j;
172: }
173:
174: if (mddev->level == 1) {
175: /* taiking over a raid1 array-
176: * we have only one active disk
177: */
178: j = 0;
179: rdev1->new_raid_disk = j;
180: }
181:
182: if (j < 0) {
183: pr_warn("md/raid0:%s: remove inactive devices before converting to RAID0\n",
184: mdname(mddev));
185: goto abort;
186: }
187: if (j >= mddev->raid_disks) {
188: pr_warn("md/raid0:%s: bad disk number %d - aborting!\n",
189: mdname(mddev), j);
190: goto abort;
191: }
192: if (dev[j]) {
193: pr_warn("md/raid0:%s: multiple devices for %d - aborting!\n",
194: mdname(mddev), j);
195: goto abort;
196: }
197: dev[j] = rdev1;
198:
199: if (!smallest || (rdev1->sectors < smallest->sectors))
200: smallest = rdev1;
201: cnt++;
202: }
203: if (cnt != mddev->raid_disks) {
204: pr_warn("md/raid0:%s: too few disks (%d of %d) - aborting!\n",
205: mdname(mddev), cnt, mddev->raid_disks);
206: goto abort;
207: }
208: zone->nb_dev = cnt;
209: zone->zone_end = smallest->sectors * cnt;
210:
211: curr_zone_end = zone->zone_end;
212:
213: /* now do the other zones */
214: for (i = 1; i < conf->nr_strip_zones; i++)
215: {
216: int j;
217:
218: zone = conf->strip_zone + i;
219: dev = conf->devlist + i * mddev->raid_disks;
220:
221: pr_debug("md/raid0:%s: zone %d\n", mdname(mddev), i);
222: zone->dev_start = smallest->sectors;
223: smallest = NULL;
224: c = 0;
225:
226: for (j=0; j<cnt; j++) {
227: rdev = conf->devlist[j];
228: if (rdev->sectors <= zone->dev_start) {
229: pr_debug("md/raid0:%s: checking %pg ... nope\n",
230: mdname(mddev),
231: rdev->bdev);
232: continue;
233: }
234: pr_debug("md/raid0:%s: checking %pg ..."
235: " contained as device %d\n",
236: mdname(mddev),
237: rdev->bdev, c);
238: dev[c] = rdev;
239: c++;
240: if (!smallest || rdev->sectors < smallest->sectors) {
241: smallest = rdev;
242: pr_debug("md/raid0:%s: (%llu) is smallest!.\n",
243: mdname(mddev),
244: (unsigned long long)rdev->sectors);
245: }
246: }
247:
248: zone->nb_dev = c;
249: sectors = (smallest->sectors - zone->dev_start) * c;
250: pr_debug("md/raid0:%s: zone->nb_dev: %d, sectors: %llu\n",
251: mdname(mddev),
252: zone->nb_dev, (unsigned long long)sectors);
253:
254: curr_zone_end += sectors;
255: zone->zone_end = curr_zone_end;
256:
257: pr_debug("md/raid0:%s: current zone start: %llu\n",
258: mdname(mddev),
259: (unsigned long long)smallest->sectors);
260: }
261:
262: if (conf->nr_strip_zones == 1 || conf->strip_zone[1].nb_dev == 1) {
263: conf->layout = RAID0_ORIG_LAYOUT;
264: } else if (mddev->layout == RAID0_ORIG_LAYOUT ||
265: mddev->layout == RAID0_ALT_MULTIZONE_LAYOUT) {
266: conf->layout = mddev->layout;
267: } else if (default_layout == RAID0_ORIG_LAYOUT ||
268: default_layout == RAID0_ALT_MULTIZONE_LAYOUT) {
269: conf->layout = default_layout;
270: } else {
271: pr_err("md/raid0:%s: cannot assemble multi-zone RAID0 with default_layout setting\n",
272: mdname(mddev));
273: pr_err("md/raid0: please set raid0.default_layout to 1 or 2\n");
274: err = -EOPNOTSUPP;
275: goto abort;
276: }
277:
278: if (conf->layout == RAID0_ORIG_LAYOUT) {
279: for (i = 1; i < conf->nr_strip_zones; i++) {
280: sector_t first_sector = conf->strip_zone[i-1].zone_end;
281:
282: sector_div(first_sector, mddev->chunk_sectors);
283: zone = conf->strip_zone + i;
284: /* disk_shift is first disk index used in the zone */
285: zone->disk_shift = sector_div(first_sector,
286: zone->nb_dev);
287: }
288: }
289:
290: pr_debug("md/raid0:%s: done.\n", mdname(mddev));
291: *private_conf = conf;
292:
293: return 0;
294: abort:
295: kvfree(conf->strip_zone);
296: kvfree(conf->devlist);
297: kfree(conf);
298: *private_conf = ERR_PTR(err);
299: return err;
300: }
SourceFile:drivers/md/raid0.c]
|
| 8/2 |
2026/08/30 01:14 |
llm |
expert |
0m
Model:
Tokens:
input: 11857
output: 36
thoughts: 244
Thoughts: **Investigating a Potential Kernel Memory Allocation Issue**
Okay, so I've got a warning popping up at `mm/slub.c:6908` within `__kvmalloc_node_noprof`. The call trace leads me to `create_strip_zones+0xb6f/0x2170`, which resides in `drivers/md/raid0.c` at line 150. Let's take a look at the code there:
```c
150: conf->devlist = kvzalloc(array3_size(sizeof(struct md_rdev *),
151: conf->nr_strip_zones,
152: mddev->raid_disks),
153: GFP_KERNEL);
```
Aha! It's using `array3_size` to compute the size for a `kvzalloc` allocation. My spider senses are tingling. That function performs a simple multiplication: `a * b * c`. If this overflows, `array3_size` returns `SIZE_MAX`. Now, `kvzalloc` called with `SIZE_MAX` is definitely going to cause an issue because it's too large and, from what I know, `__GFP_NOWARN` wasn't used. This warning in `__kvmalloc_node_noprof` makes total sense in that case. I need to dive deeper into `array3_size` now.
|
| 9/2 |
2026/08/30 01:14 |
tool |
codesearch-definition-source |
0m
Error:
Args: map[ContextFile:drivers/md/raid0.c Name:array3_size]
Results: map[SourceCode: SourceFile:]
|
| 10/2 |
2026/08/30 01:14 |
llm |
expert |
0m
Model:
Tokens:
input: 12485
output: 35
thoughts: 18
Thoughts: Here's my thinking:
**Finding the Definition of `array3_size`**
Okay, so I need to find where the `array3_size` definition resides. Given that it's likely dealing with size calculations, and from past experience, I'd bet it's tucked away in the Linux kernel's include files, probably those related to overflow prevention. The naming convention strongly suggests `include/linux/overflow.h`. That's the most logical place to start digging. I'll check there first.
|
| 11/2 |
2026/08/30 01:14 |
tool |
codesearch-definition-source |
0m
Error:
Args: map[ContextFile:include/linux/overflow.h Name:array3_size]
Results: map[SourceCode: SourceFile:]
|
| 12/2 |
2026/08/30 01:14 |
llm |
expert |
0m
Model:
Tokens:
input: 12671
output: 18
thoughts: 11
Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience:
**Analyzing the Codebase for `array3_size`**
Okay, so I need to understand where `array3_size` is used. A quick `grep` for that string seems like the most efficient way to start. It's the standard, go-to approach when you're looking for variable usage. This will give me a list of all instances of the string `array3_size` in the codebase. From there, I can quickly identify the relevant files and surrounding context. I'll be particularly interested in how it's defined, initialized, and, crucially, how it’s being *used*. Is it a hard-coded value, a result of some calculation, or derived from some other array/structure? Knowing that will greatly inform how I approach any further analysis or debugging. This should be a pretty rapid way to gain context.
|
| 13/2 |
2026/08/30 01:14 |
tool |
grepper |
0m
Args: map[Expression:array3_size]
Results: map[Output:Documentation/core-api/memory-allocation.rst=138=allocate memory for an array, there are kmalloc_array() and kcalloc()
Documentation/core-api/memory-allocation.rst:139:helpers. The helpers struct_size(), array_size() and array3_size() can
Documentation/core-api/memory-allocation.rst-140-be used to safely calculate object sizes without overflowing.
--
Documentation/process/deprecated.rst=102=Instead, use the helpers::
--
Documentation/process/deprecated.rst-107-
Documentation/process/deprecated.rst:108:For more details, also see array3_size() and flex_array_size(),
Documentation/process/deprecated.rst-109-as well as the related check_mul_overflow(), check_add_overflow(),
--
Documentation/translations/it_IT/process/deprecated.rst=111=dovreste scrivere:
--
Documentation/translations/it_IT/process/deprecated.rst-116-
Documentation/translations/it_IT/process/deprecated.rst:117:Per maggiori dettagli fate riferimento a array3_size() e flex_array_size(), ma
Documentation/translations/it_IT/process/deprecated.rst-118-anche le funzioni della famiglia check_mul_overflow(), check_add_overflow(),
--
Documentation/translations/pt_BR/process/deprecated.rst=101=Em vez disso, use os auxiliares::
--
Documentation/translations/pt_BR/process/deprecated.rst-106-
Documentation/translations/pt_BR/process/deprecated.rst:107:Para mais detalhes, veja também array3_size() e flex_array_size(), bem como as
Documentation/translations/pt_BR/process/deprecated.rst-108-funções relacionadas das famílias check_mul_overflow(), check_add_overflow(),
--
Documentation/translations/sp_SP/process/deprecated.rst=109=Re-escríbase, como::
--
Documentation/translations/sp_SP/process/deprecated.rst-114-
Documentation/translations/sp_SP/process/deprecated.rst:115:Para más detalles, mire también array3_size() y flex_array_size(),
Documentation/translations/sp_SP/process/deprecated.rst-116-como también la familia de funciones relacionadas check_mul_overflow(),
--
Documentation/translations/zh_CN/core-api/memory-allocation.rst=76=GFP标志和回收行为
--
Documentation/translations/zh_CN/core-api/memory-allocation.rst-110-设置为零的例程，如kzalloc()。如果你需要为一个数组分配内存，有kmalloc_array()和kcalloc()
Documentation/translations/zh_CN/core-api/memory-allocation.rst:111:辅助程序。辅助程序struct_size()、array_size()和array3_size()可以用来安全地计算对
Documentation/translations/zh_CN/core-api/memory-allocation.rst-112-象的大小而不会溢出。
--
drivers/crypto/intel/qat/qat_common/adf_heartbeat.c=51=static bool validate_hb_ctrs_cnt(struct adf_accel_dev *accel_dev)
--
drivers/crypto/intel/qat/qat_common/adf_heartbeat.c-55- const size_t hb_struct_size = sizeof(struct hb_cnt_pair);
drivers/crypto/intel/qat/qat_common/adf_heartbeat.c:56: const size_t exp_diff_size = array3_size(ADF_NUM_PKE_STRAND, max_aes,
drivers/crypto/intel/qat/qat_common/adf_heartbeat.c-57- hb_struct_size);
--
drivers/devfreq/devfreq.c=795=struct devfreq *devfreq_add_device(struct device *dev,
--
drivers/devfreq/devfreq.c-885- devfreq->stats.trans_table = devm_kzalloc(&devfreq->dev,
drivers/devfreq/devfreq.c:886: array3_size(sizeof(unsigned int),
drivers/devfreq/devfreq.c-887- devfreq->max_state,
--
drivers/devfreq/devfreq.c=1761=static ssize_t trans_stat_store(struct device *dev,
--
drivers/devfreq/devfreq.c-1780- sizeof(*df->stats.time_in_state)));
drivers/devfreq/devfreq.c:1781: memset(df->stats.trans_table, 0, array3_size(sizeof(unsigned int),
drivers/devfreq/devfreq.c-1782- df->max_state,
--
drivers/gpu/drm/nouveau/nvkm/core/event.c=201=__nvkm_event_init(const struct nvkm_event_func *func, struct nvkm_subdev *subdev,
--
drivers/gpu/drm/nouveau/nvkm/core/event.c-203-{
drivers/gpu/drm/nouveau/nvkm/core/event.c:204: event->refs = kzalloc(array3_size(index_nr, types_nr, sizeof(*event->refs)), GFP_KERNEL);
drivers/gpu/drm/nouveau/nvkm/core/event.c-205- if (!event->refs)
--
drivers/hid/hid-core.c=154=static int open_collection(struct hid_parser *parser, unsigned type)
--
drivers/hid/hid-core.c-178- collection = kmalloc(
drivers/hid/hid-core.c:179: array3_size(sizeof(struct hid_collection),
drivers/hid/hid-core.c-180- parser->device->collection_size,
--
drivers/hwmon/i5k_amb.c=243=static int i5k_amb_hwmon_init(struct platform_device *pdev)
--
drivers/hwmon/i5k_amb.c-256- /* Set up sysfs stuff */
drivers/hwmon/i5k_amb.c:257: data->attrs = kzalloc(array3_size(num_ambs, KNOBS_PER_AMB,
drivers/hwmon/i5k_amb.c-258- sizeof(*data->attrs)),
--
drivers/hwmon/nct6683.c=414=nct6683_create_attr_group(struct device *dev,
--
drivers/hwmon/nct6683.c-444-
drivers/hwmon/nct6683.c:445: su = devm_kzalloc(dev, array3_size(repeat, count, sizeof(*su)),
drivers/hwmon/nct6683.c-446- GFP_KERNEL);
--
drivers/hwmon/nct6775-core.c=1076=static int nct6775_add_template_attr_group(struct device *dev, struct nct6775_data *data,
--
drivers/hwmon/nct6775-core.c-1105-
drivers/hwmon/nct6775-core.c:1106: su = devm_kzalloc(dev, array3_size(repeat, count, sizeof(*su)),
drivers/hwmon/nct6775-core.c-1107- GFP_KERNEL);
--
drivers/iio/adc/max1363.c=1453=static int max1363_alloc_scan_masks(struct iio_dev *indio_dev)
--
drivers/iio/adc/max1363.c-1459- masks = devm_kzalloc(&indio_dev->dev,
drivers/iio/adc/max1363.c:1460: array3_size(BITS_TO_LONGS(MAX1363_MAX_CHANNELS),
drivers/iio/adc/max1363.c-1461- sizeof(long),
--
drivers/input/rmi4/rmi_f54.c=680=static int rmi_f54_probe(struct rmi_function *fn)
--
drivers/input/rmi4/rmi_f54.c-701- tx = f54->num_tx_electrodes;
drivers/input/rmi4/rmi_f54.c:702: f54->max_report_size = array3_size(tx, rx, sizeof(u16));
drivers/input/rmi4/rmi_f54.c-703- f54->report_data = devm_kzalloc(&fn->dev, f54->max_report_size,
--
drivers/md/bcache/super.c=2244=static int cache_alloc(struct cache *ca)
--
drivers/md/bcache/super.c-2344-
drivers/md/bcache/super.c:2345: ca->prio_buckets = kzalloc(array3_size(sizeof(uint64_t),
drivers/md/bcache/super.c-2346- prio_buckets(ca), 2),
--
drivers/md/raid0.c=66=static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
--
drivers/md/raid0.c-149- goto abort;
drivers/md/raid0.c:150: conf->devlist = kvzalloc(array3_size(sizeof(struct md_rdev *),
drivers/md/raid0.c-151- conf->nr_strip_zones,
--
drivers/md/raid1.c=3045=static struct r1conf *setup_conf(struct mddev *mddev)
--
drivers/md/raid1.c-3073-
drivers/md/raid1.c:3074: conf->mirrors = kzalloc(array3_size(sizeof(struct raid1_info),
drivers/md/raid1.c-3075- mddev->raid_disks, 2),
--
drivers/md/raid1.c=3315=static int raid1_reshape(struct mddev *mddev)
--
drivers/md/raid1.c-3364- }
drivers/md/raid1.c:3365: newmirrors = kzalloc(array3_size(sizeof(struct raid1_info),
drivers/md/raid1.c-3366- raid_disks, 2),
--
drivers/media/common/v4l2-tpg/v4l2-tpg-core.c=112=int tpg_alloc(struct tpg_data *tpg, unsigned max_w)
--
drivers/media/common/v4l2-tpg/v4l2-tpg-core.c-123- tpg->lines[pat][plane] =
drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:124: vzalloc(array3_size(max_w, 2, pixelsz));
drivers/media/common/v4l2-tpg/v4l2-tpg-core.c-125- if (!tpg->lines[pat][plane]) {
--
drivers/media/common/v4l2-tpg/v4l2-tpg-core.c-131- tpg->downsampled_lines[pat][plane] =
drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:132: vzalloc(array3_size(max_w, 2, pixelsz));
drivers/media/common/v4l2-tpg/v4l2-tpg-core.c-133- if (!tpg->downsampled_lines[pat][plane]) {
--
drivers/media/common/v4l2-tpg/v4l2-tpg-core.c-154- tpg->random_line[plane] =
drivers/media/common/v4l2-tpg/v4l2-tpg-core.c:155: vzalloc(array3_size(max_w, 2, pixelsz));
drivers/media/common/v4l2-tpg/v4l2-tpg-core.c-156- if (!tpg->random_line[plane]) {
--
drivers/mfd/motorola-cpcap.c=168=static int cpcap_init_irq(struct cpcap_ddata *cpcap)
--
drivers/mfd/motorola-cpcap.c-172- cpcap->irqs = devm_kzalloc(&cpcap->spi->dev,
drivers/mfd/motorola-cpcap.c:173: array3_size(sizeof(*cpcap->irqs),
drivers/mfd/motorola-cpcap.c-174- CPCAP_NR_IRQ_REG_BANKS,
--
drivers/net/ethernet/hisilicon/hns/hns_enet.c=2102=static int hns_nic_init_ring_data(struct hns_nic_priv *priv)
--
drivers/net/ethernet/hisilicon/hns/hns_enet.c-2113-
drivers/net/ethernet/hisilicon/hns/hns_enet.c:2114: priv->ring_data = kzalloc(array3_size(h->q_num,
drivers/net/ethernet/hisilicon/hns/hns_enet.c-2115- sizeof(*priv->ring_data), 2),
--
drivers/net/ethernet/hisilicon/hns3/hns3_enet.c=4993=static int hns3_get_ring_config(struct hns3_nic_priv *priv)
--
drivers/net/ethernet/hisilicon/hns3/hns3_enet.c-4999- priv->ring = devm_kzalloc(&pdev->dev,
drivers/net/ethernet/hisilicon/hns3/hns3_enet.c:5000: array3_size(h->kinfo.num_tqps,
drivers/net/ethernet/hisilicon/hns3/hns3_enet.c-5001- sizeof(*priv->ring), 2),
--
drivers/net/ethernet/netronome/nfp/abm/ctrl.c=347=nfp_abm_ctrl_find_q_rtsym(struct nfp_abm *abm, const char *name_fmt,
--
drivers/net/ethernet/netronome/nfp/abm/ctrl.c-351-
drivers/net/ethernet/netronome/nfp/abm/ctrl.c:352: size = array3_size(size, abm->num_bands, NFP_NET_MAX_RX_RINGS);
drivers/net/ethernet/netronome/nfp/abm/ctrl.c-353- snprintf(pf_symbol, sizeof(pf_symbol), name_fmt,
--
drivers/nvmem/rockchip-efuse.c=95=static int rockchip_rk3328_efuse_read(void *context, unsigned int offset,
--
drivers/nvmem/rockchip-efuse.c-116-
drivers/nvmem/rockchip-efuse.c:117: buf = kzalloc(array3_size(addr_len, RK3399_NBYTES, sizeof(*buf)),
drivers/nvmem/rockchip-efuse.c-118- GFP_KERNEL);
--
drivers/nvmem/rockchip-efuse.c=150=static int rockchip_rk3399_efuse_read(void *context, unsigned int offset,
--
drivers/nvmem/rockchip-efuse.c-169-
drivers/nvmem/rockchip-efuse.c:170: buf = kzalloc(array3_size(addr_len, RK3399_NBYTES, sizeof(*buf)),
drivers/nvmem/rockchip-efuse.c-171- GFP_KERNEL);
--
drivers/pinctrl/pinctrl-lantiq.c=148=static int ltq_pinctrl_dt_node_to_map(struct pinctrl_dev *pctldev,
--
drivers/pinctrl/pinctrl-lantiq.c-158- max_maps += ltq_pinctrl_dt_subnode_size(np);
drivers/pinctrl/pinctrl-lantiq.c:159: *map = kzalloc(array3_size(max_maps, sizeof(struct pinctrl_map), 2),
drivers/pinctrl/pinctrl-lantiq.c-160- GFP_KERNEL);
--
drivers/pinctrl/pinctrl-single.c=1119=static int pcs_parse_bits_in_pinctrl_entry(struct pcs_device *pcs,
--
drivers/pinctrl/pinctrl-single.c-1144- vals = devm_kzalloc(pcs->dev,
drivers/pinctrl/pinctrl-single.c:1145: array3_size(rows, npins_in_row, sizeof(*vals)),
drivers/pinctrl/pinctrl-single.c-1146- GFP_KERNEL);
--
drivers/pinctrl/pinctrl-single.c-1150- pins = devm_kzalloc(pcs->dev,
drivers/pinctrl/pinctrl-single.c:1151: array3_size(rows, npins_in_row, sizeof(*pins)),
drivers/pinctrl/pinctrl-single.c-1152- GFP_KERNEL);
--
drivers/pinctrl/samsung/pinctrl-samsung.c=919=static int samsung_pinctrl_register(struct platform_device *pdev,
--
drivers/pinctrl/samsung/pinctrl-samsung.c-950- pin_names = devm_kzalloc(&pdev->dev,
drivers/pinctrl/samsung/pinctrl-samsung.c:951: array3_size(sizeof(char), PIN_NAME_LENGTH,
drivers/pinctrl/samsung/pinctrl-samsung.c-952- drvdata->nr_pins),
--
drivers/scsi/fnic/fnic_debugfs.c=197=static int fnic_trace_debugfs_open(struct inode *inode,
--
drivers/scsi/fnic/fnic_debugfs.c-207- if (*rdata_ptr == fc_trc_flag->fnic_trace) {
drivers/scsi/fnic/fnic_debugfs.c:208: fnic_dbg_prt->buffer = vzalloc(array3_size(3, trace_max_pages,
drivers/scsi/fnic/fnic_debugfs.c-209- PAGE_SIZE));
--
drivers/scsi/fnic/fnic_debugfs.c-216- fnic_dbg_prt->buffer =
drivers/scsi/fnic/fnic_debugfs.c:217: vzalloc(array3_size(3, fnic_fc_trace_max_pages,
drivers/scsi/fnic/fnic_debugfs.c-218- PAGE_SIZE));
--
drivers/soc/fsl/qbman/qman.c=1105=int qman_alloc_fq_table(u32 _num_fqids)
--
drivers/soc/fsl/qbman/qman.c-1108-
drivers/soc/fsl/qbman/qman.c:1109: fq_table = vzalloc(array3_size(sizeof(struct qman_fq *),
drivers/soc/fsl/qbman/qman.c-1110- num_fqids, 2));
--
drivers/staging/media/atomisp/pci/sh_css_param_dvs.c=16=alloc_dvs_6axis_table(const struct ia_css_resolution *frame_res,
--
drivers/staging/media/atomisp/pci/sh_css_param_dvs.c-51- /* Generate Y buffers */
drivers/staging/media/atomisp/pci/sh_css_param_dvs.c:52: dvs_config->xcoords_y = kvmalloc(array3_size(width_y, height_y, sizeof(uint32_t)),
drivers/staging/media/atomisp/pci/sh_css_param_dvs.c-53- GFP_KERNEL);
--
drivers/staging/media/atomisp/pci/sh_css_param_dvs.c-59-
drivers/staging/media/atomisp/pci/sh_css_param_dvs.c:60: dvs_config->ycoords_y = kvmalloc(array3_size(width_y, height_y, sizeof(uint32_t)),
drivers/staging/media/atomisp/pci/sh_css_param_dvs.c-61- GFP_KERNEL);
--
drivers/staging/media/atomisp/pci/sh_css_param_dvs.c-70-
drivers/staging/media/atomisp/pci/sh_css_param_dvs.c:71: dvs_config->xcoords_uv = kvmalloc(array3_size(width_uv, height_uv,
drivers/staging/media/atomisp/pci/sh_css_param_dvs.c-72- sizeof(uint32_t)),
--
drivers/staging/media/atomisp/pci/sh_css_param_dvs.c-79-
drivers/staging/media/atomisp/pci/sh_css_param_dvs.c:80: dvs_config->ycoords_uv = kvmalloc(array3_size(width_uv, height_uv,
drivers/staging/media/atomisp/pci/sh_css_param_dvs.c-81- sizeof(uint32_t)),
--
drivers/staging/media/atomisp/pci/sh_css_param_shading.c=329=ia_css_shading_table_alloc(
--
drivers/staging/media/atomisp/pci/sh_css_param_shading.c-348- me->data[i] =
drivers/staging/media/atomisp/pci/sh_css_param_shading.c:349: kvmalloc(array3_size(width, height,
drivers/staging/media/atomisp/pci/sh_css_param_shading.c-350- sizeof(*me->data[0])),
--
drivers/staging/media/atomisp/pci/sh_css_params.c=93=static size_t fpntbl_bytes(const struct ia_css_binary *binary)
drivers/staging/media/atomisp/pci/sh_css_params.c-94-{
drivers/staging/media/atomisp/pci/sh_css_params.c:95: return array3_size(sizeof(char),
drivers/staging/media/atomisp/pci/sh_css_params.c-96- binary->in_frame_info.res.height,
--
drivers/staging/media/atomisp/pci/sh_css_params.c=100=static size_t sctbl_bytes(const struct ia_css_binary *binary)
--
drivers/staging/media/atomisp/pci/sh_css_params.c-102- return size_mul(sizeof(unsigned short),
drivers/staging/media/atomisp/pci/sh_css_params.c:103: array3_size(binary->sctbl_height,
drivers/staging/media/atomisp/pci/sh_css_params.c-104- binary->sctbl_aligned_width_per_color,
--
drivers/staging/media/atomisp/pci/sh_css_params.c=108=static size_t morph_plane_bytes(const struct ia_css_binary *binary)
drivers/staging/media/atomisp/pci/sh_css_params.c-109-{
drivers/staging/media/atomisp/pci/sh_css_params.c:110: return array3_size(SH_CSS_MORPH_TABLE_ELEM_BYTES,
drivers/staging/media/atomisp/pci/sh_css_params.c-111- binary->morph_tbl_aligned_width,
--
drivers/staging/media/atomisp/pci/sh_css_params.c=924=sh_css_set_black_frame(struct ia_css_stream *stream,
--
drivers/staging/media/atomisp/pci/sh_css_params.c-951- if (!params->fpn_config.data) {
drivers/staging/media/atomisp/pci/sh_css_params.c:952: params->fpn_config.data = kvmalloc(array3_size(height, width, sizeof(short)),
drivers/staging/media/atomisp/pci/sh_css_params.c-953- GFP_KERNEL);
--
drivers/staging/media/atomisp/pci/sh_css_params.c=1361=struct ia_css_morph_table *ia_css_morph_table_allocate(
--
drivers/staging/media/atomisp/pci/sh_css_params.c-1381- for (i = 0; i < IA_CSS_MORPH_TABLE_NUM_PLANES; i++) {
drivers/staging/media/atomisp/pci/sh_css_params.c:1382: me->coordinates_x[i] = kvmalloc(array3_size(height, width,
drivers/staging/media/atomisp/pci/sh_css_params.c-1383- sizeof(*me->coordinates_x[i])),
drivers/staging/media/atomisp/pci/sh_css_params.c-1384- GFP_KERNEL);
drivers/staging/media/atomisp/pci/sh_css_params.c:1385: me->coordinates_y[i] = kvmalloc(array3_size(height, width,
drivers/staging/media/atomisp/pci/sh_css_params.c-1386- sizeof(*me->coordinates_y[i])),
--
drivers/staging/media/atomisp/pci/sh_css_params.c=4194=ia_css_dvs_statistics_allocate(const struct ia_css_dvs_grid_info *grid)
--
drivers/staging/media/atomisp/pci/sh_css_params.c-4204- me->grid = *grid;
drivers/staging/media/atomisp/pci/sh_css_params.c:4205: me->hor_proj = kvmalloc(array3_size(grid->height,
drivers/staging/media/atomisp/pci/sh_css_params.c-4206- IA_CSS_DVS_NUM_COEF_TYPES,
--
drivers/staging/media/atomisp/pci/sh_css_params.c-4211-
drivers/staging/media/atomisp/pci/sh_css_params.c:4212: me->ver_proj = kvmalloc(array3_size(grid->width,
drivers/staging/media/atomisp/pci/sh_css_params.c-4213- IA_CSS_DVS_NUM_COEF_TYPES,
--
drivers/staging/media/atomisp/pci/sh_css_params.c=4451=ia_css_dvs2_6axis_config_allocate(const struct ia_css_stream *stream)
--
drivers/staging/media/atomisp/pci/sh_css_params.c-4480- IA_CSS_LOG("table UV: W %d H %d", width_uv, height_uv);
drivers/staging/media/atomisp/pci/sh_css_params.c:4481: dvs_config->xcoords_y = kvmalloc(array3_size(width_y, height_y,
drivers/staging/media/atomisp/pci/sh_css_params.c-4482- sizeof(uint32_t)),
--
drivers/staging/media/atomisp/pci/sh_css_params.c-4486-
drivers/staging/media/atomisp/pci/sh_css_params.c:4487: dvs_config->ycoords_y = kvmalloc(array3_size(width_y, height_y,
drivers/staging/media/atomisp/pci/sh_css_params.c-4488- sizeof(uint32_t)),
--
drivers/staging/media/atomisp/pci/sh_css_params.c-4492-
drivers/staging/media/atomisp/pci/sh_css_params.c:4493: dvs_config->xcoords_uv = kvmalloc(array3_size(width_uv, height_uv,
drivers/staging/media/atomisp/pci/sh_css_params.c-4494- sizeof(uint32_t)),
--
drivers/staging/media/atomisp/pci/sh_css_params.c-4498-
drivers/staging/media/atomisp/pci/sh_css_params.c:4499: dvs_config->ycoords_uv = kvmalloc(array3_size(width_uv, height_uv,
drivers/staging/media/atomisp/pci/sh_css_params.c-4500- sizeof(uint32_t)),
--
drivers/video/fbdev/core/fbcon.c=641=static void fbcon_prepare_logo(struct vc_data *vc, struct fb_info *info,
--
drivers/video/fbdev/core/fbcon.c-669- if (r != q && new_rows >= rows + logo_lines) {
drivers/video/fbdev/core/fbcon.c:670: save = kmalloc(array3_size(logo_lines, new_cols, 2),
drivers/video/fbdev/core/fbcon.c-671- GFP_KERNEL);
--
drivers/video/fbdev/core/fbcon.c-673- int i = min(cols, new_cols);
drivers/video/fbdev/core/fbcon.c:674: scr_memsetw(save, erase, array3_size(logo_lines, new_cols, 2));
drivers/video/fbdev/core/fbcon.c-675- r = q - step;
--
drivers/video/fbdev/core/fbcon.c-710- rows);
drivers/video/fbdev/core/fbcon.c:711: scr_memcpyw(q, save, array3_size(logo_lines, new_cols, 2));
drivers/video/fbdev/core/fbcon.c-712- vc->state.y += logo_lines;
--
fs/afs/cmservice.c=190=static int afs_deliver_cb_callback(struct afs_call *call)
--
fs/afs/cmservice.c-215-
fs/afs/cmservice.c:216: call->buffer = kmalloc(array3_size(call->count, 3, 4),
fs/afs/cmservice.c-217- GFP_KERNEL);
--
fs/ocfs2/sysfile.c=40=static struct inode **get_local_system_inode(struct ocfs2_super *osb,
--
fs/ocfs2/sysfile.c-56- local_system_inodes =
fs/ocfs2/sysfile.c:57: kzalloc(array3_size(sizeof(struct inode *),
fs/ocfs2/sysfile.c-58- NUM_LOCAL_SYSTEM_INODES,
--
include/linux/overflow.h=370=static __always_inline size_t __must_check size_sub(size_t minuend, size_t subtrahend)
--
include/linux/overflow.h-393-/**
include/linux/overflow.h:394: * array3_size() - Calculate size of 3-dimensional array.
include/linux/overflow.h-395- * @a: dimension one
--
include/linux/overflow.h-403- */
include/linux/overflow.h:404:#define array3_size(a, b, c) size_mul(size_mul(a, b), c)
include/linux/overflow.h-405-
--
lib/test_firmware.c=922=static ssize_t trigger_batched_requests_store(struct device *dev,
--
lib/test_firmware.c-937- test_fw_config->reqs =
lib/test_firmware.c:938: vzalloc(array3_size(sizeof(struct test_batched_req),
lib/test_firmware.c-939- test_fw_config->num_requests, 2));
--
lib/test_firmware.c=1025=ssize_t trigger_batched_requests_async_store(struct device *dev,
--
lib/test_firmware.c-1041- test_fw_config->reqs =
lib/test_firmware.c:1042: vzalloc(array3_size(sizeof(struct test_batched_req),
lib/test_firmware.c-1043- test_fw_config->num_requests, 2));
--
lib/test_rhashtable.c=754=static int __init test_rht_init(void)
--
lib/test_rhashtable.c-824- return -ENOMEM;
lib/test_rhashtable.c:825: objs = vzalloc(array3_size(sizeof(struct test_obj), tcount, entries));
lib/test_rhashtable.c-826- if (!objs) {
--
scripts/coccinelle/misc/array_size_dup.cocci-2-///
scripts/coccinelle/misc/array_size_dup.cocci:3:/// Check for array_size(), array3_size(), struct_size() duplicates.
scripts/coccinelle/misc/array_size_dup.cocci-4-/// These patterns are detected:
--
scripts/coccinelle/misc/array_size_dup.cocci=84=expression E1, E2, E3;
--
scripts/coccinelle/misc/array_size_dup.cocci-86-
scripts/coccinelle/misc/array_size_dup.cocci:87:array3_size(E1, E2, E3)
scripts/coccinelle/misc/array_size_dup.cocci-88-
--
scripts/coccinelle/misc/array_size_dup.cocci=95=position p1, p2;
--
scripts/coccinelle/misc/array_size_dup.cocci-100- when != &\(subE1\|subE2\|subE3\)
scripts/coccinelle/misc/array_size_dup.cocci:101:* array3_size(E1, E2, E3)@p2
scripts/coccinelle/misc/array_size_dup.cocci-102-
--
scripts/coccinelle/misc/array_size_dup.cocci=105=p2 << as3_next.p2;
--
scripts/coccinelle/misc/array_size_dup.cocci-107-
scripts/coccinelle/misc/array_size_dup.cocci:108:msg = "WARNING: array3_size is used later (line %s) to compute the same size" % (p2[0].line)
scripts/coccinelle/misc/array_size_dup.cocci-109-coccilib.report.print_report(p1[0], msg)
--
scripts/coccinelle/misc/array_size_dup.cocci=113=p2 << as3_next.p2;
--
scripts/coccinelle/misc/array_size_dup.cocci-115-
scripts/coccinelle/misc/array_size_dup.cocci:116:msg = "WARNING: array3_size is used later (line %s) to compute the same size" % (p2[0].line)
scripts/coccinelle/misc/array_size_dup.cocci-117-coccilib.org.print_todo(p1[0], msg)
--
scripts/coccinelle/misc/array_size_dup.cocci=125=position p1, p2;
--
scripts/coccinelle/misc/array_size_dup.cocci-127-
scripts/coccinelle/misc/array_size_dup.cocci:128:* array3_size(E1, E2, E3)@p1
scripts/coccinelle/misc/array_size_dup.cocci-129- ... when != \(subE1\|subE2\|subE3\) aop E4
--
scripts/coccinelle/misc/array_size_dup.cocci=135=p2 << as3_prev.p2;
--
scripts/coccinelle/misc/array_size_dup.cocci-137-
scripts/coccinelle/misc/array_size_dup.cocci:138:msg = "WARNING: array3_size is already used (line %s) to compute the same size" % (p1[0].line)
scripts/coccinelle/misc/array_size_dup.cocci-139-coccilib.report.print_report(p2[0], msg)
--
scripts/coccinelle/misc/array_size_dup.cocci=143=p2 << as3_prev.p2;
--
scripts/coccinelle/misc/array_size_dup.cocci-145-
scripts/coccinelle/misc/array_size_dup.cocci:146:msg = "WARNING: array3_size is already used (line %s) to compute the same size" % (p1[0].line)
scripts/coccinelle/misc/array_size_dup.cocci-147-coccilib.org.print_todo(p2[0], msg)
--
sound/core/oss/pcm_plugin.c=34=static int snd_pcm_plugin_alloc(struct snd_pcm_plugin *plugin, snd_pcm_uframes_t frames)
--
sound/core/oss/pcm_plugin.c-49- return width;
sound/core/oss/pcm_plugin.c:50: size = array3_size(frames, format->channels, width);
sound/core/oss/pcm_plugin.c-51- /* check for too large period size once again */
--
sound/pci/ctxfi/ctdaio.c=375=static int dao_rsc_init(struct dao *dao,
--
sound/pci/ctxfi/ctdaio.c-386-
sound/pci/ctxfi/ctdaio.c:387: dao->imappers = kzalloc(array3_size(sizeof(void *), desc->msr, 2),
sound/pci/ctxfi/ctdaio.c-388- GFP_KERNEL);
--
sound/pci/emu10k1/emu10k1_main.c=1710=static int alloc_pm_buffer(struct snd_emu10k1 *emu)
--
sound/pci/emu10k1/emu10k1_main.c-1716- size += ARRAY_SIZE(saved_regs_audigy);
sound/pci/emu10k1/emu10k1_main.c:1717: emu->saved_ptr = vmalloc(array3_size(4, NUM_G, size));
sound/pci/emu10k1/emu10k1_main.c-1718- if (!emu->saved_ptr)
--
sound/usb/line6/pcm.c=147=static int line6_buffer_acquire(struct snd_line6_pcm *line6pcm,
--
sound/usb/line6/pcm.c-157- pstr->buffer =
sound/usb/line6/pcm.c:158: kmalloc(array3_size(line6pcm->line6->iso_buffers,
sound/usb/line6/pcm.c-159- LINE6_ISO_PACKETS, pkt_size),
--
tools/include/linux/overflow.h=102=static inline __must_check size_t array_size(size_t a, size_t b)
--
tools/include/linux/overflow.h-112-/**
tools/include/linux/overflow.h:113: * array3_size() - Calculate size of 3-dimensional array.
tools/include/linux/overflow.h-114- *
--
tools/include/linux/overflow.h-123- */
tools/include/linux/overflow.h:124:static inline __must_check size_t array3_size(size_t a, size_t b, size_t c)
tools/include/linux/overflow.h-125-{
]
|
| 14/2 |
2026/08/30 01:14 |
llm |
expert |
0m
Model:
Tokens:
input: 23366
output: 39
thoughts: 507
Thoughts: **Analyzing Potential Overflow in `create_strip_zones`**
Okay, so I'm looking at this `create_strip_zones` function, specifically the memory allocation part using `kvzalloc`. I see `array3_size` is used to calculate the allocation size, which is defined in `include/linux/overflow.h`. Let's break this down.
The core of it is `array3_size(sizeof(struct md_rdev *), conf->nr_strip_zones, mddev->raid_disks)`. `sizeof(struct md_rdev *)` is 8 bytes on a 64-bit system, which is what I'm assuming. `conf->nr_strip_zones` and `mddev->raid_disks` are, as far as the current code shows, `int`s. This means potentially, if these values are large enough, multiplying them could lead to an integer overflow.
`array3_size` uses `size_mul`, which, thankfully, returns `SIZE_MAX` if it detects an overflow. If overflow occurs, the result will be `SIZE_MAX`. So, in a 64-bit architecture, `SIZE_MAX` is `2^64 - 1`.
The initial concern was that `8 * nr_strip_zones * raid_disks` could overflow `SIZE_MAX`. But wait, the crucial part is that `nr_strip_zones` and `raid_disks` are 32-bit `int`s. So, the maximum multiplication would be `8 * 2^31 * 2^31 = 2^65`. This is larger than `SIZE_MAX`. The calculation will definitely overflow if large enough numbers are used, but the `size_mul` function handles the overflow.
Okay, so we have this potentially very large size passed to `kvzalloc`. If the size calculation overflows to `SIZE_MAX`, `kvzalloc` calls `__kvmalloc_node_noprof` with `SIZE_MAX`. Now, what does `__kvmalloc_node_noprof` do with this massive size? The code says `if (size > INT_MAX)`, it sets the `__GFP_NOWARN` flag. Why is that? I should probably look at the implementation of `__kvmalloc_node_noprof` in `mm/slub.c` or `mm/util.c` to understand the implications of this warning flag. Perhaps it's suppressing an overly aggressive warning when requesting a large memory allocation, I'll check that.
|
| 15/2 |
2026/08/30 01:14 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:mm/slub.c Name:__kvmalloc_node_noprof]
Results: map[SourceCode:6885: void *__kvmalloc_node_noprof(DECL_KMALLOC_PARAMS(size, b, token), unsigned long align,
6886: gfp_t flags, int node)
6887: {
6888: bool allow_block;
6889: void *ret;
6890: const struct slab_alloc_context ac = {
6891: .caller_addr = _RET_IP_,
6892: .orig_size = size,
6893: .alloc_flags = SLAB_ALLOC_DEFAULT,
6894: };
6895:
6896: /*
6897: * It doesn't really make sense to fallback to vmalloc for sub page
6898: * requests
6899: */
6900: ret = __do_kmalloc_node(PASS_BUCKET_PARAM(b),
6901: kmalloc_gfp_adjust(flags, size),
6902: node, PASS_TOKEN_PARAM(token), &ac);
6903: if (ret || size <= PAGE_SIZE)
6904: return ret;
6905:
6906: /* Don't even allow crazy sizes */
6907: if (unlikely(size > INT_MAX)) {
6908: WARN_ON_ONCE(!(flags & __GFP_NOWARN));
6909: return NULL;
6910: }
6911:
6912: /*
6913: * For non-blocking the VM_ALLOW_HUGE_VMAP is not used
6914: * because the huge-mapping path in vmalloc contains at
6915: * least one might_sleep() call.
6916: *
6917: * TODO: Revise huge-mapping path to support non-blocking
6918: * flags.
6919: */
6920: allow_block = gfpflags_allow_blocking(flags);
6921:
6922: /*
6923: * kvmalloc() can always use VM_ALLOW_HUGE_VMAP,
6924: * since the callers already cannot assume anything
6925: * about the resulting pointer, and cannot play
6926: * protection games.
6927: */
6928: return __vmalloc_node_range_noprof(size, align, VMALLOC_START, VMALLOC_END,
6929: flags, PAGE_KERNEL, allow_block ? VM_ALLOW_HUGE_VMAP:0,
6930: node, __builtin_return_address(0));
6931: }
SourceFile:mm/slub.c]
|
| 16/2 |
2026/08/30 01:14 |
llm |
expert |
0m
Model:
Tokens:
input: 25214
output: 34
thoughts: 356
Thoughts: **Analyzing Potential Integer Overflow in RAID0 Zone Creation**
Okay, so I'm looking at this `__kvmalloc_node_noprof` function. It has a check: if the size requested is greater than `INT_MAX`, and `__GFP_NOWARN` is *not* set, it throws a warning. Makes sense, prevents crazy allocations.
Now, let's connect this to the `create_strip_zones` function, specifically this line:
```c
conf->devlist = kvzalloc(array3_size(sizeof(struct md_rdev *), conf->nr_strip_zones, mddev->raid_disks), GFP_KERNEL);
```
`kvzalloc` uses `GFP_KERNEL`, which doesn't have the `__GFP_NOWARN` flag. So if the size calculated by `array3_size` exceeds `INT_MAX`, we'll get that warning. Ah, and if `array3_size` overflows, it returns `SIZE_MAX`, which *definitely* exceeds `INT_MAX`, so that triggers the warning immediately. Even if it doesn't overflow, if the multiplication of `8 * nr_strip_zones * raid_disks` exceeds `INT_MAX`, we'll have a problem.
So, the key here is `nr_strip_zones` and `mddev->raid_disks`. How are those controlled? Let's trace it back. Okay, we've got `md_ioctl` -> `do_md_run` -> `md_run` -> `raid0_run` -> `create_strip_zones`. So the user, through `md_ioctl`, is ultimately controlling `mddev->raid_disks`. That's where the vulnerability lies, isn't it? The user is setting up the RAID configuration.
|
| 17/2 |
2026/08/30 01:15 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/md/md.c Name:md_ioctl]
Results: map[SourceCode:8342: static int md_ioctl(struct block_device *bdev, blk_mode_t mode,
8343: unsigned int cmd, unsigned long arg)
8344: {
8345: int err = 0;
8346: unsigned int noio_flags = 0;
8347: void __user *argp = (void __user *)arg;
8348: struct mddev *mddev = NULL;
8349: bool suspend;
8350:
8351: err = md_ioctl_valid(cmd);
8352: if (err)
8353: return err;
8354:
8355: /*
8356: * Commands dealing with the RAID driver but not any
8357: * particular array:
8358: */
8359: if (cmd == RAID_VERSION)
8360: return get_version(argp);
8361:
8362: /*
8363: * Commands creating/starting a new array:
8364: */
8365:
8366: mddev = bdev->bd_disk->private_data;
8367:
8368: /* Some actions do not requires the mutex */
8369: switch (cmd) {
8370: case GET_ARRAY_INFO:
8371: if (!mddev->raid_disks && !mddev->external)
8372: return -ENODEV;
8373: return get_array_info(mddev, argp);
8374:
8375: case GET_DISK_INFO:
8376: if (!mddev->raid_disks && !mddev->external)
8377: return -ENODEV;
8378: return get_disk_info(mddev, argp);
8379:
8380: case SET_DISK_FAULTY:
8381: return set_disk_faulty(mddev, new_decode_dev(arg));
8382:
8383: case GET_BITMAP_FILE:
8384: return get_bitmap_file(mddev, argp);
8385: }
8386:
8387: if (cmd == STOP_ARRAY || cmd == STOP_ARRAY_RO) {
8388: /* Need to flush page cache, and ensure no-one else opens
8389: * and writes
8390: */
8391: err = mddev_set_closing_and_sync_blockdev(mddev, 1);
8392: if (err)
8393: return err;
8394: }
8395:
8396: if (!md_is_rdwr(mddev))
8397: flush_work(&mddev->sync_work);
8398:
8399: suspend = md_ioctl_need_suspend(cmd);
8400: err = suspend ? mddev_suspend_and_lock(mddev) : mddev_lock(mddev);
8401: if (err) {
8402: pr_debug("md: ioctl lock interrupted, reason %d, cmd %d\n",
8403: err, cmd);
8404: goto out;
8405: }
8406: if (suspend)
8407: noio_flags = memalloc_noio_save();
8408:
8409: if (cmd == SET_ARRAY_INFO) {
8410: err = __md_set_array_info(mddev, argp);
8411: goto unlock;
8412: }
8413:
8414: /*
8415: * Commands querying/configuring an existing array:
8416: */
8417: /* if we are not initialised yet, only ADD_NEW_DISK, STOP_ARRAY,
8418: * RUN_ARRAY, and GET_ and SET_BITMAP_FILE are allowed */
8419: if ((!mddev->raid_disks && !mddev->external)
8420: && cmd != ADD_NEW_DISK && cmd != STOP_ARRAY
8421: && cmd != RUN_ARRAY && cmd != SET_BITMAP_FILE
8422: && cmd != GET_BITMAP_FILE) {
8423: err = -ENODEV;
8424: goto unlock;
8425: }
8426:
8427: /*
8428: * Commands even a read-only array can execute:
8429: */
8430: switch (cmd) {
8431: case RESTART_ARRAY_RW:
8432: err = restart_array(mddev);
8433: goto unlock;
8434:
8435: case STOP_ARRAY:
8436: err = do_md_stop(mddev, 0);
8437: goto unlock;
8438:
8439: case STOP_ARRAY_RO:
8440: if (mddev->pers)
8441: err = md_set_readonly(mddev);
8442: goto unlock;
8443:
8444: case HOT_REMOVE_DISK:
8445: err = hot_remove_disk(mddev, new_decode_dev(arg));
8446: goto unlock;
8447:
8448: case ADD_NEW_DISK:
8449: /* We can support ADD_NEW_DISK on read-only arrays
8450: * only if we are re-adding a preexisting device.
8451: * So require mddev->pers and MD_DISK_SYNC.
8452: */
8453: if (mddev->pers) {
8454: mdu_disk_info_t info;
8455: if (copy_from_user(&info, argp, sizeof(info)))
8456: err = -EFAULT;
8457: else if (!(info.state & (1<<MD_DISK_SYNC)))
8458: /* Need to clear read-only for this */
8459: break;
8460: else
8461: err = md_add_new_disk(mddev, &info);
8462: goto unlock;
8463: }
8464: break;
8465: }
8466:
8467: /*
8468: * The remaining ioctls are changing the state of the
8469: * superblock, so we do not allow them on read-only arrays.
8470: */
8471: if (!md_is_rdwr(mddev) && mddev->pers) {
8472: if (mddev->ro != MD_AUTO_READ) {
8473: err = -EROFS;
8474: goto unlock;
8475: }
8476: mddev->ro = MD_RDWR;
8477: sysfs_notify_dirent_safe(mddev->sysfs_state);
8478: set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
8479: /* mddev_unlock will wake thread */
8480: /* If a device failed while we were read-only, we
8481: * need to make sure the metadata is updated now.
8482: */
8483: if (test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags)) {
8484: mddev_unlock(mddev);
8485: wait_event(mddev->sb_wait,
8486: !test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags) &&
8487: !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags));
8488: mddev_lock_nointr(mddev);
8489: }
8490: }
8491:
8492: switch (cmd) {
8493: case ADD_NEW_DISK:
8494: {
8495: mdu_disk_info_t info;
8496: if (copy_from_user(&info, argp, sizeof(info)))
8497: err = -EFAULT;
8498: else
8499: err = md_add_new_disk(mddev, &info);
8500: goto unlock;
8501: }
8502:
8503: case CLUSTERED_DISK_NACK:
8504: if (mddev_is_clustered(mddev))
8505: mddev->cluster_ops->new_disk_ack(mddev, false);
8506: else
8507: err = -EINVAL;
8508: goto unlock;
8509:
8510: case HOT_ADD_DISK:
8511: err = hot_add_disk(mddev, new_decode_dev(arg));
8512: goto unlock;
8513:
8514: case RUN_ARRAY:
8515: err = do_md_run(mddev);
8516: goto unlock;
8517:
8518: case SET_BITMAP_FILE:
8519: err = set_bitmap_file(mddev, (int)arg);
8520: goto unlock;
8521:
8522: default:
8523: err = -EINVAL;
8524: goto unlock;
8525: }
8526:
8527: unlock:
8528: if (mddev->hold_active == UNTIL_IOCTL &&
8529: err != -EINVAL)
8530: mddev->hold_active = 0;
8531:
8532: if (suspend) {
8533: memalloc_noio_restore(noio_flags);
8534: mddev_unlock_and_resume(mddev);
8535: } else {
8536: mddev_unlock(mddev);
8537: }
8538:
8539: out:
8540: if (cmd == STOP_ARRAY_RO || (err && cmd == STOP_ARRAY))
8541: clear_bit(MD_CLOSING, &mddev->flags);
8542: return err;
8543: }
SourceFile:drivers/md/md.c]
|
| 18/2 |
2026/08/30 01:15 |
llm |
expert |
0m
Model:
Tokens:
input: 28902
output: 33
thoughts: 44
Thoughts: Okay, here's my interpretation of those thoughts, presented as my own mental process, with the bolded header as requested:
**Investigating `md_ioctl` and Its Privilege Requirements**
Alright, so `md_ioctl` apparently needs `CAP_SYS_ADMIN`. I need to figure out why, and if that's the *only* place we see that sort of restriction. Let's trace it down. My first thought is to check `blkdev_ioctl` or `vfs_ioctl` directly, just to see the context. Ah, `md_ioctl` gets called from `blkdev_ioctl`. That narrows down the scope quite a bit, so I'll start with that. This means the root of the issue is probably at the `blkdev_ioctl` level. Now, why would *that* need it? Time to dig into the relationship between the two and how it relates to general device control.
|
| 19/2 |
2026/08/30 01:15 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:block/ioctl.c Name:blkdev_ioctl]
Results: map[SourceCode: 744: /*
745: * Always keep this in sync with compat_blkdev_ioctl()
746: * to handle all incompatible commands in both functions.
747: *
748: * New commands must be compatible and go into blkdev_common_ioctl
749: */
750: long blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
751: {
752: struct block_device *bdev = I_BDEV(file->f_mapping->host);
753: void __user *argp = (void __user *)arg;
754: blk_mode_t mode = file_to_blk_mode(file);
755: int ret;
756:
757: switch (cmd) {
758: /* These need separate implementations for the data structure */
759: case HDIO_GETGEO:
760: return blkdev_getgeo(bdev, argp);
761: case BLKPG:
762: return blkpg_ioctl(bdev, argp);
763:
764: /* Compat mode returns 32-bit data instead of 'long' */
765: case BLKRAGET:
766: case BLKFRAGET:
767: if (!argp)
768: return -EINVAL;
769: return put_long(argp,
770: (bdev->bd_disk->bdi->ra_pages * PAGE_SIZE) / 512);
771: case BLKGETSIZE:
772: if (bdev_nr_sectors(bdev) > ~0UL)
773: return -EFBIG;
774: return put_ulong(argp, bdev_nr_sectors(bdev));
775:
776: /* The data is compatible, but the command number is different */
777: case BLKBSZGET: /* get block device soft block size (cf. BLKSSZGET) */
778: return put_int(argp, block_size(bdev));
779: case BLKBSZSET:
780: return blkdev_bszset(file, mode, argp);
781: case BLKGETSIZE64:
782: return put_u64(argp, bdev_nr_bytes(bdev));
783:
784: /* Incompatible alignment on i386 */
785: case BLKTRACESETUP:
786: case BLKTRACESETUP2:
787: return blk_trace_ioctl(bdev, cmd, argp);
788: default:
789: break;
790: }
791:
792: ret = blkdev_common_ioctl(bdev, mode, cmd, arg, argp);
793: if (ret != -ENOIOCTLCMD)
794: return ret;
795:
796: if (!bdev->bd_disk->fops->ioctl)
797: return -ENOTTY;
798: return bdev->bd_disk->fops->ioctl(bdev, mode, cmd, arg);
799: }
SourceFile:block/ioctl.c]
|
| 20/2 |
2026/08/30 01:15 |
llm |
expert |
0m
Model:
Tokens:
input: 30115
output: 36
thoughts: 49
Thoughts: **Analyzing the Block Device IOCTL Call in the RAID Context**
Okay, so I'm tracing through this block device operation, and the `bdev->bd_disk->fops->ioctl` function is being invoked. Right, that's the standard entry point for IOCTL calls. Given this is an MD device, I'm expecting `md_ioctl` to be the handler. Now the question is, is this `md_ioctl` restricted to root access? I know there are security considerations around IOCTLs, especially in the context of RAID where you can modify the underlying storage configuration. I need to make sure this isn't exploitable. Let's see... I'll check the `md_ioctl_valid` function to confirm if we validate if we are root before running this ioctl.
|
| 21/2 |
2026/08/30 01:15 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/md/md.c Name:md_ioctl_valid]
Results: map[SourceCode:8267: static inline int md_ioctl_valid(unsigned int cmd)
8268: {
8269: switch (cmd) {
8270: case GET_ARRAY_INFO:
8271: case GET_DISK_INFO:
8272: case RAID_VERSION:
8273: return 0;
8274: case ADD_NEW_DISK:
8275: case GET_BITMAP_FILE:
8276: case HOT_ADD_DISK:
8277: case HOT_REMOVE_DISK:
8278: case RESTART_ARRAY_RW:
8279: case RUN_ARRAY:
8280: case SET_ARRAY_INFO:
8281: case SET_BITMAP_FILE:
8282: case SET_DISK_FAULTY:
8283: case STOP_ARRAY:
8284: case STOP_ARRAY_RO:
8285: case CLUSTERED_DISK_NACK:
8286: if (!capable(CAP_SYS_ADMIN))
8287: return -EACCES;
8288: return 0;
8289: default:
8290: return -ENOTTY;
8291: }
8292: }
SourceFile:drivers/md/md.c]
|
| 22/2 |
2026/08/30 01:15 |
llm |
expert |
0m
Model:
Tokens:
input: 30740
output: 21
thoughts: 366
Thoughts: **Analyzing the Vulnerability's Accessibility**
Okay, so `md_ioctl_valid` is checking for `CAP_SYS_ADMIN` when dealing with array modifications, like `RUN_ARRAY`. That means this specific bug *requires* that privilege within the initial user namespace, right? Since it's using `capable()`, not `ns_capable()`. Got it. So the vulnerability shouldn't be exploitable from unprivileged processes or within user namespaces. This is because `capable()` is tied to the initial user namespace. Let me quickly verify that `capable` checks `init_user_ns`. Yes, confirmed.
Now, let me think through if there are any *other* ways to get to `create_strip_zones`. That's where the real risk lies, because if there's another path, it could bypass the intended restriction.
`create_strip_zones` is called by `raid0_run`. `raid0_run` is part of `raid0_personality`. And that function gets called from `md_run` when the array is started. `md_run` is called by `do_md_run` (via the `RUN_ARRAY` ioctl), or from `autorun_devices` or `autorun_array`. And `autorun_array` itself is called by `md_autodetect_dev` during boot or module load. Okay, no `md_start_sync`. And definitely not triggered by mounting a file system; md arrays are block devices.
Could a malicious USB device trigger this? If a USB device pretends to be a block device, and the system has md autodetect enabled, it might try to assemble an md array. I should really check `md_autodetect_dev` closely.
|
| 23/2 |
2026/08/30 01:15 |
tool |
codesearch-find-references |
0m
Args:
Results: map[References:[map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:do_md_run SourceFile:drivers/md/md.c SourceLine:6880] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:raid_ctr SourceFile:drivers/md/dm-raid.c SourceLine:3261] map[ReferenceKind:takes-address-of ReferencingEntityKind:global_variable ReferencingEntityName:__UNIQUE_ID_addressable_md_run_1349 SourceFile:drivers/md/md.c SourceLine:6873] map[ReferenceKind:takes-address-of ReferencingEntityKind:global_variable ReferencingEntityName:__gendwarfksyms_ptr_md_run SourceFile:drivers/md/md.c SourceLine:6873] map[ReferenceKind:takes-address-of ReferencingEntityKind:global_variable ReferencingEntityName:__gendwarfksyms_ptr_md_run SourceFile:drivers/md/md.c SourceLine:6873]] TruncatedOutput:false]
|
| 24/2 |
2026/08/30 01:15 |
llm |
expert |
0m
Model:
Tokens:
input: 31817
output: 38
thoughts: 79
Thoughts: Here's my summary, as I understand the situation:
**Understanding the dm-raid Target Creation and Security Context**
Okay, so I'm looking at how dm-raid targets are created and how that interacts with the overall system security. From what I'm seeing in `dm-raid.c`, the `md_run` function is being invoked from `raid_ctr`, and that makes sense – `raid_ctr` is the constructor for those dm-raid targets. That tracks; when we create a new RAID setup, we need to initialize it somehow.
The interesting bit, the one I need to focus on, is that these dm-raid targets are created, ultimately, through device-mapper ioctls. And *that* part is key, because those ioctls are behind a `CAP_SYS_ADMIN` restriction. So, any user-space process trying to spin up a RAID device has to have elevated privileges, which is standard practice for device-mapper control, but worth confirming.
Now, I'm going to shift my focus to `dm_ctl_ioctl`, because that's where the rubber meets the road. It looks like the main point of control. I need to understand what's happening within that ioctl handler to make sure everything's secure and that there aren't any potential vulnerabilities in the target creation process.
|
| 25/2 |
2026/08/30 01:15 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/md/dm-ioctl.c Name:dm_ctl_ioctl]
Results: map[SourceCode:2233: static long dm_ctl_ioctl(struct file *file, uint command, ulong u)
2234: {
2235: return (long)ctl_ioctl(file, command, (struct dm_ioctl __user *)u);
2236: }
SourceFile:drivers/md/dm-ioctl.c]
|
| 26/2 |
2026/08/30 01:15 |
llm |
expert |
0m
Model:
Tokens:
input: 32324
output: 36
thoughts: 9
Thoughts: Okay, here's my attempt at summarizing that thought process, keeping in mind I'm speaking to a fellow expert:
**Investigating `ctl_ioctl`**
Alright, time to dig into this. My initial thought is to zero in on `ctl_ioctl`. It's the logical place to start when dealing with... *this* kind of interaction. I need to refresh my understanding of its role, specifically within the context of [your field - implied by your expertise]. I'm thinking about the low-level implications, the potential for... well, you know, everything that could be going on down there. Let's see what we can find. I’ll start by reviewing the documentation and maybe then trace it back to see what is happening in those layers, and how it effects other components. It is time to dive in!
|
| 27/2 |
2026/08/30 01:15 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/md/dm-ioctl.c Name:ctl_ioctl]
Results: map[SourceCode:2159: static int ctl_ioctl(struct file *file, uint command, struct dm_ioctl __user *user)
2160: {
2161: int r = 0;
2162: int ioctl_flags;
2163: int param_flags;
2164: unsigned int cmd;
2165: struct dm_ioctl *param;
2166: ioctl_fn fn = NULL;
2167: size_t input_param_size;
2168: struct dm_ioctl param_kernel;
2169:
2170: /* only root can play with this */
2171: if (!capable(CAP_SYS_ADMIN))
2172: return -EACCES;
2173:
2174: if (_IOC_TYPE(command) != DM_IOCTL)
2175: return -ENOTTY;
2176:
2177: cmd = _IOC_NR(command);
2178:
2179: /*
2180: * Check the interface version passed in. This also
2181: * writes out the kernel's interface version.
2182: */
2183: r = check_version(cmd, user, ¶m_kernel);
2184: if (r)
2185: return r;
2186:
2187: /*
2188: * Nothing more to do for the version command.
2189: */
2190: if (cmd == DM_VERSION_CMD)
2191: return 0;
2192:
2193: fn = lookup_ioctl(cmd, &ioctl_flags);
2194: if (!fn) {
2195: DMERR("dm_ctl_ioctl: unknown command 0x%x", command);
2196: return -ENOTTY;
2197: }
2198:
2199: /*
2200: * Copy the parameters into kernel space.
2201: */
2202: r = copy_params(user, ¶m_kernel, ioctl_flags, ¶m, ¶m_flags);
2203:
2204: if (r)
2205: return r;
2206:
2207: input_param_size = param->data_size;
2208: r = validate_params(cmd, param);
2209: if (r)
2210: goto out;
2211:
2212: param->data_size = offsetof(struct dm_ioctl, data);
2213: r = fn(file, param, input_param_size);
2214:
2215: if (unlikely(param->flags & DM_BUFFER_FULL_FLAG) &&
2216: unlikely(ioctl_flags & IOCTL_FLAGS_NO_PARAMS))
2217: DMERR("ioctl %d tried to output some data but has IOCTL_FLAGS_NO_PARAMS set", cmd);
2218:
2219: if (!r && ioctl_flags & IOCTL_FLAGS_ISSUE_GLOBAL_EVENT)
2220: dm_issue_global_event();
2221:
2222: /*
2223: * Copy the results back to userland.
2224: */
2225: if (!r && copy_to_user(user, param, param->data_size))
2226: r = -EFAULT;
2227:
2228: out:
2229: free_params(param, input_param_size, param_flags);
2230: return r;
2231: }
SourceFile:drivers/md/dm-ioctl.c]
|
| 28/2 |
2026/08/30 01:15 |
llm |
expert |
0m
Model:
Tokens:
input: 33583
output: 42
thoughts: 41
Thoughts: Okay, here's my take on those thoughts, framed as my own:
**Analyzing `ctl_ioctl` and MD Autodetection**
Right, so `ctl_ioctl` does indeed check for `capable(CAP_SYS_ADMIN)`. That's standard practice, I'd expect nothing less, given the potential for system-level impact of I/O control operations.
But hold on, my primary concern is MD autodetect. Let's shift focus. I need to refresh my memory on the specifics of `md_autodetect_dev`. Time to dig into that code path and make sure I fully understand it. I need to trace through the relevant functions to see if there are any potential vulnerabilities or unexpected behaviors within that process. Time to get to work.
|
| 29/2 |
2026/08/30 01:15 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/md/md-autodetect.c Name:md_autodetect_dev]
Results: map[SourceCode:11000: void md_autodetect_dev(dev_t dev)
11001: {
11002: struct detected_devices_node *node_detected_dev;
11003:
11004: node_detected_dev = kzalloc_obj(*node_detected_dev);
11005: if (node_detected_dev) {
11006: node_detected_dev->dev = dev;
11007: mutex_lock(&detected_devices_mutex);
11008: list_add_tail(&node_detected_dev->list, &all_detected_devices);
11009: mutex_unlock(&detected_devices_mutex);
11010: }
11011: }
SourceFile:drivers/md/md.c]
|
| 30/2 |
2026/08/30 01:15 |
llm |
expert |
0m
Model:
Tokens:
input: 34064
output: 25
thoughts: 16
Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience:
**Tracing the Origins of `md_autodetect_dev`**
Okay, so I need to understand where `md_autodetect_dev` is being invoked. It's a critical function, no doubt, given its name. I need to figure out the call chain, and what situations trigger its execution. Is it called during initial boot, module loading, or perhaps in response to a hotplug event? Understanding the context will be key to diagnosing whatever issue I'm looking at. I'll need to use my usual tools - `grep`, `tracepoints`, the kernel source, and maybe even a debugger if I have to, to pinpoint exactly where this function gets its hooks into the system. This is often where things get interesting and debugging gets real.
|
| 31/2 |
2026/08/30 01:15 |
tool |
codesearch-find-references |
0m
Args: map[Name:md_autodetect_dev]
Results: map[References:[map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:blk_add_partition SourceFile:block/partitions/core.c SourceLine:578] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:export_rdev SourceFile:drivers/md/md.c SourceLine:2655]] TruncatedOutput:false]
|
| 32/2 |
2026/08/30 01:15 |
llm |
expert |
0m
Model:
Tokens:
input: 34401
output: 36
thoughts: 22
Thoughts: Here's a summary of my understanding, framed from my perspective as an expert:
**Understanding the Partition Addition Call**
Okay, so I'm tracking down where this partition addition process begins. From what I'm seeing, `blk_add_partition` in `block/partitions/core.c` is the entry point. That's good, that's what I expected. This function is the one responsible for registering a new partition within the block layer's partition management framework. Knowing the exact function and file helps me understand the context of the entire flow: It's the core function responsible for hooking up a new partition to the block device. Now I can start tracing its arguments, understand its internal calls, and see how the partition data is actually incorporated into the structures. This is a solid starting point for debugging or extending this particular functionality.
|
| 33/2 |
2026/08/30 01:15 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:block/partitions/core.c Name:blk_add_partition]
Results: map[SourceCode: 531: static bool blk_add_partition(struct gendisk *disk,
532: struct parsed_partitions *state, int p)
533: {
534: sector_t size = state->parts[p].size;
535: sector_t from = state->parts[p].from;
536: struct block_device *part;
537:
538: if (!size)
539: return true;
540:
541: if (from >= get_capacity(disk)) {
542: printk(KERN_WARNING
543: "%s: p%d start %llu is beyond EOD, ",
544: disk->disk_name, p, (unsigned long long) from);
545: if (disk_unlock_native_capacity(disk))
546: return false;
547: return true;
548: }
549:
550: if (from + size > get_capacity(disk)) {
551: printk(KERN_WARNING
552: "%s: p%d size %llu extends beyond EOD, ",
553: disk->disk_name, p, (unsigned long long) size);
554:
555: if (disk_unlock_native_capacity(disk))
556: return false;
557:
558: /*
559: * We can not ignore partitions of broken tables created by for
560: * example camera firmware, but we limit them to the end of the
561: * disk to avoid creating invalid block devices.
562: */
563: size = get_capacity(disk) - from;
564: }
565:
566: part = add_partition(disk, p, from, size, state->parts[p].flags,
567: &state->parts[p].info);
568: if (IS_ERR(part)) {
569: if (PTR_ERR(part) != -ENXIO) {
570: printk(KERN_ERR " %s: p%d could not be added: %pe\n",
571: disk->disk_name, p, part);
572: }
573: return true;
574: }
575:
576: if (IS_BUILTIN(CONFIG_BLK_DEV_MD) &&
577: (state->parts[p].flags & ADDPART_FLAG_RAID))
578: md_autodetect_dev(part->bd_dev);
579:
580: return true;
581: }
SourceFile:block/partitions/core.c]
|
| 34/2 |
2026/08/30 01:15 |
llm |
expert |
0m
Model:
Tokens:
input: 35421
output: 23
thoughts: 143
Thoughts: **My Analysis of RAID Autodetection**
Okay, so here's what's happening. When the system's parsing partitions, if it encounters a partition with the `ADDPART_FLAG_RAID` flag set, it triggers a call to `md_autodetect_dev`. I know that `ADDPART_FLAG_RAID` is set during the partition parsing stage, specifically when it sees partition types like 0xfd in an MBR partition table – the classic Linux RAID autodetect signature. So, if a user pops in a USB drive with that familiar 0xfd MBR type, boom, `md_autodetect_dev` gets invoked.
But then I stop. `md_autodetect_dev` just *adds* the device to `all_detected_devices`? It's not *doing* anything beyond that initial registration. I need to figure out the orchestration of how this list is *processed*. Where does the actual autodetect logic *happen*? What's consuming `all_detected_devices`? I better check `autodetect_raid` to see where the magic happens.
|
| 35/2 |
2026/08/30 01:16 |
tool |
codesearch-find-references |
0m
Args: map[Name:autodetect_raid]
Results: map[References:[map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:md_run_setup SourceFile:drivers/md/md-autodetect.c SourceLine:279]] TruncatedOutput:false]
|
| 36/2 |
2026/08/30 01:16 |
llm |
expert |
0m
Model:
Tokens:
input: 35907
output: 40
thoughts: 11
Thoughts: Okay, here's my take on those thoughts, tailored for an expert audience, presented in the first person:
**Checking `md_run_setup`**
Alright, time to dive in. My first thought is to zero in on `md_run_setup`. It's the lynchpin, isn't it? Everything crucial for the molecular dynamics run hinges on that. Before I do anything else, I need to make sure the setup parameters are sane. Let's see if the input files are being parsed correctly, if the integration timestep is reasonable for the system, if the thermostats and barostats are configured as intended, the cutoff radii are appropriate given the forcefield and system size and the initial conditions are what I expected, and if the simulation length is what I'm aiming for. I have to verify that the initialization for parallel runs is proceeding as expected and that the communication topology is set correctly. Any subtle error in any of these settings could lead to garbage out, or worse, make the simulation unstable. We all know the pain of running a multi-day simulation just to find a critical error buried in the setup. Let's make sure this is smooth.
|
| 37/2 |
2026/08/30 01:16 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/md/md-autodetect.c Name:md_run_setup]
Results: map[SourceCode: 272: void __init md_run_setup(void)
273: {
274: int ent;
275:
276: if (raid_noautodetect)
277: printk(KERN_INFO "md: Skipping autodetection of RAID arrays. (raid=autodetect will force)\n");
278: else
279: autodetect_raid();
280:
281: for (ent = 0; ent < md_setup_ents; ent++)
282: md_setup_drive(&md_setup_args[ent]);
283: }
SourceFile:drivers/md/md-autodetect.c]
|
| 38/2 |
2026/08/30 01:16 |
llm |
expert |
0m
Model:
Tokens:
input: 36410
output: 23
thoughts: 35
Thoughts: Okay, here's my take on those thoughts, framed as an expert's internal monologue:
**Boot-Time Raid Initialization Review**
Right, so `md_run_setup` is clearly the initialization routine, the `__init__` for the RAID configuration during the system's boot process. The immediate question is, where else does `autodetect_raid` get invoked? Is this part of the standard boot sequence, or is it triggered on specific events? I need to understand the call graph of that function to ensure that the RAID autodetection isn't happening redundantly or, worse, at the wrong time. Is it possible that there's another point where raid autodetection can take place, potentially conflicting with this init stage? I need to check the codebase to confirm if any other components are calling `autodetect_raid`.
|
| 39/2 |
2026/08/30 01:16 |
tool |
codesearch-find-references |
0m
Args: map[Name:all_detected_devices]
Results: map[References:<nil> TruncatedOutput:false]
|
| 40/2 |
2026/08/30 01:16 |
llm |
expert |
0m
Model:
Tokens:
input: 36662
output: 34
thoughts: 50
Thoughts: Okay, let me think this through.
**Investigating RAID Autodetection**
Hmm, I see `all_detected_devices` is being utilized within `autodetect_raid`. Right, that makes sense – it's feeding the potential candidates. The question now is: is there an ioctl command lurking around that *triggers* this autodetection process? I need to figure out if there's a way to initiate it directly, perhaps programmatically. My instincts tell me the place to look would be within the `md_ioctl` handler, as that's where the core RAID management interfaces are likely defined. Let's see if there's a constant or definition along the lines of `RAID_AUTORUN` in there. That would be the smoking gun I'm looking for.
|
| 41/2 |
2026/08/30 01:16 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/md/md.c Name:md_ioctl]
Results: map[SourceCode:8342: static int md_ioctl(struct block_device *bdev, blk_mode_t mode,
8343: unsigned int cmd, unsigned long arg)
8344: {
8345: int err = 0;
8346: unsigned int noio_flags = 0;
8347: void __user *argp = (void __user *)arg;
8348: struct mddev *mddev = NULL;
8349: bool suspend;
8350:
8351: err = md_ioctl_valid(cmd);
8352: if (err)
8353: return err;
8354:
8355: /*
8356: * Commands dealing with the RAID driver but not any
8357: * particular array:
8358: */
8359: if (cmd == RAID_VERSION)
8360: return get_version(argp);
8361:
8362: /*
8363: * Commands creating/starting a new array:
8364: */
8365:
8366: mddev = bdev->bd_disk->private_data;
8367:
8368: /* Some actions do not requires the mutex */
8369: switch (cmd) {
8370: case GET_ARRAY_INFO:
8371: if (!mddev->raid_disks && !mddev->external)
8372: return -ENODEV;
8373: return get_array_info(mddev, argp);
8374:
8375: case GET_DISK_INFO:
8376: if (!mddev->raid_disks && !mddev->external)
8377: return -ENODEV;
8378: return get_disk_info(mddev, argp);
8379:
8380: case SET_DISK_FAULTY:
8381: return set_disk_faulty(mddev, new_decode_dev(arg));
8382:
8383: case GET_BITMAP_FILE:
8384: return get_bitmap_file(mddev, argp);
8385: }
8386:
8387: if (cmd == STOP_ARRAY || cmd == STOP_ARRAY_RO) {
8388: /* Need to flush page cache, and ensure no-one else opens
8389: * and writes
8390: */
8391: err = mddev_set_closing_and_sync_blockdev(mddev, 1);
8392: if (err)
8393: return err;
8394: }
8395:
8396: if (!md_is_rdwr(mddev))
8397: flush_work(&mddev->sync_work);
8398:
8399: suspend = md_ioctl_need_suspend(cmd);
8400: err = suspend ? mddev_suspend_and_lock(mddev) : mddev_lock(mddev);
8401: if (err) {
8402: pr_debug("md: ioctl lock interrupted, reason %d, cmd %d\n",
8403: err, cmd);
8404: goto out;
8405: }
8406: if (suspend)
8407: noio_flags = memalloc_noio_save();
8408:
8409: if (cmd == SET_ARRAY_INFO) {
8410: err = __md_set_array_info(mddev, argp);
8411: goto unlock;
8412: }
8413:
8414: /*
8415: * Commands querying/configuring an existing array:
8416: */
8417: /* if we are not initialised yet, only ADD_NEW_DISK, STOP_ARRAY,
8418: * RUN_ARRAY, and GET_ and SET_BITMAP_FILE are allowed */
8419: if ((!mddev->raid_disks && !mddev->external)
8420: && cmd != ADD_NEW_DISK && cmd != STOP_ARRAY
8421: && cmd != RUN_ARRAY && cmd != SET_BITMAP_FILE
8422: && cmd != GET_BITMAP_FILE) {
8423: err = -ENODEV;
8424: goto unlock;
8425: }
8426:
8427: /*
8428: * Commands even a read-only array can execute:
8429: */
8430: switch (cmd) {
8431: case RESTART_ARRAY_RW:
8432: err = restart_array(mddev);
8433: goto unlock;
8434:
8435: case STOP_ARRAY:
8436: err = do_md_stop(mddev, 0);
8437: goto unlock;
8438:
8439: case STOP_ARRAY_RO:
8440: if (mddev->pers)
8441: err = md_set_readonly(mddev);
8442: goto unlock;
8443:
8444: case HOT_REMOVE_DISK:
8445: err = hot_remove_disk(mddev, new_decode_dev(arg));
8446: goto unlock;
8447:
8448: case ADD_NEW_DISK:
8449: /* We can support ADD_NEW_DISK on read-only arrays
8450: * only if we are re-adding a preexisting device.
8451: * So require mddev->pers and MD_DISK_SYNC.
8452: */
8453: if (mddev->pers) {
8454: mdu_disk_info_t info;
8455: if (copy_from_user(&info, argp, sizeof(info)))
8456: err = -EFAULT;
8457: else if (!(info.state & (1<<MD_DISK_SYNC)))
8458: /* Need to clear read-only for this */
8459: break;
8460: else
8461: err = md_add_new_disk(mddev, &info);
8462: goto unlock;
8463: }
8464: break;
8465: }
8466:
8467: /*
8468: * The remaining ioctls are changing the state of the
8469: * superblock, so we do not allow them on read-only arrays.
8470: */
8471: if (!md_is_rdwr(mddev) && mddev->pers) {
8472: if (mddev->ro != MD_AUTO_READ) {
8473: err = -EROFS;
8474: goto unlock;
8475: }
8476: mddev->ro = MD_RDWR;
8477: sysfs_notify_dirent_safe(mddev->sysfs_state);
8478: set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
8479: /* mddev_unlock will wake thread */
8480: /* If a device failed while we were read-only, we
8481: * need to make sure the metadata is updated now.
8482: */
8483: if (test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags)) {
8484: mddev_unlock(mddev);
8485: wait_event(mddev->sb_wait,
8486: !test_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags) &&
8487: !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags));
8488: mddev_lock_nointr(mddev);
8489: }
8490: }
8491:
8492: switch (cmd) {
8493: case ADD_NEW_DISK:
8494: {
8495: mdu_disk_info_t info;
8496: if (copy_from_user(&info, argp, sizeof(info)))
8497: err = -EFAULT;
8498: else
8499: err = md_add_new_disk(mddev, &info);
8500: goto unlock;
8501: }
8502:
8503: case CLUSTERED_DISK_NACK:
8504: if (mddev_is_clustered(mddev))
8505: mddev->cluster_ops->new_disk_ack(mddev, false);
8506: else
8507: err = -EINVAL;
8508: goto unlock;
8509:
8510: case HOT_ADD_DISK:
8511: err = hot_add_disk(mddev, new_decode_dev(arg));
8512: goto unlock;
8513:
8514: case RUN_ARRAY:
8515: err = do_md_run(mddev);
8516: goto unlock;
8517:
8518: case SET_BITMAP_FILE:
8519: err = set_bitmap_file(mddev, (int)arg);
8520: goto unlock;
8521:
8522: default:
8523: err = -EINVAL;
8524: goto unlock;
8525: }
8526:
8527: unlock:
8528: if (mddev->hold_active == UNTIL_IOCTL &&
8529: err != -EINVAL)
8530: mddev->hold_active = 0;
8531:
8532: if (suspend) {
8533: memalloc_noio_restore(noio_flags);
8534: mddev_unlock_and_resume(mddev);
8535: } else {
8536: mddev_unlock(mddev);
8537: }
8538:
8539: out:
8540: if (cmd == STOP_ARRAY_RO || (err && cmd == STOP_ARRAY))
8541: clear_bit(MD_CLOSING, &mddev->flags);
8542: return err;
8543: }
SourceFile:drivers/md/md.c]
|
| 42/2 |
2026/08/30 01:16 |
llm |
expert |
0m
Model:
Tokens:
input: 39815
output: 24
thoughts: 101
Thoughts: **Investigating RAID_AUTORUN ioctl Handling**
Okay, so I'm digging into how `RAID_AUTORUN` is managed, and it hits me that it's an ioctl. First, I need to verify its validity using `md_ioctl_valid`. Let's see... Yup, that checks out. Now, where is it *actually* processed? My initial thought was that it would be handled in `md_ioctl`, given that it's an ioctl, but, looking at the switch statement in there, it's not present. Hmm... that's unexpected. Wait a minute... does `autodetect_raid` handle this? That sounds plausible. Time to do a quick search and confirm my suspicions about `RAID_AUTORUN`.
|
| 43/2 |
2026/08/30 01:16 |
tool |
codesearch-find-references |
0m
Error:
Args:
Results: map[References:<nil> TruncatedOutput:false]
|
| 44/2 |
2026/08/30 01:16 |
llm |
expert |
0m
Model:
Tokens:
input: 40129
output: 20
thoughts: 13
Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience:
**Analyzing the `RAID_AUTORUN` Configuration**
Okay, so I'm thinking about this `RAID_AUTORUN` variable. My gut says it's likely a configuration flag related to automated RAID array management. I need to get a better handle on where it's defined and how it's being used within the system. To do that, I'm going to reach for `grep`. It's the quickest and dirtiest way to pinpoint the source of that string within the codebase. Hopefully, it will return the config file and the program using that configuration variable, or just the variable's source code, depending on how that flag is being used. From there, I can get a better feel for its intent.
|
| 45/2 |
2026/08/30 01:16 |
tool |
grepper |
0m
Args: map[Expression:RAID_AUTORUN]
Results: map[Output:include/uapi/linux/raid/md_u.h-38-#define GET_DISK_INFO _IOR (MD_MAJOR, 0x12, mdu_disk_info_t)
include/uapi/linux/raid/md_u.h:39:#define RAID_AUTORUN _IO (MD_MAJOR, 0x14)
include/uapi/linux/raid/md_u.h-40-#define GET_BITMAP_FILE _IOR (MD_MAJOR, 0x15, mdu_bitmap_file_t)
]
|
| 46/2 |
2026/08/30 01:16 |
llm |
expert |
0m
Model:
Tokens:
input: 40483
output: 20
thoughts: 12
Thoughts: Okay, here's my take on those thoughts, tailored for an expert audience, presented in the first person:
**Investigating RAID_AUTORUN Usage**
Alright, so the first thing I'm thinking is, "Where exactly is this `RAID_AUTORUN` variable being leveraged within the system?" This isn't just a casual curiosity; I need to understand its scope and impact. I'm mentally running through potential areas. Is it a kernel module parameter? A user-space daemon configuration setting? Part of a boot script or initramfs process? Or maybe even something baked into the firmware itself?
I'm thinking, "Is this part of the standard RAID implementation or a custom solution?" This will help narrow down the search. Understanding its context is crucial because `RAID_AUTORUN` could have a profound effect on RAID behavior, particularly during system initialization or recovery. It could be about automatic array assembly, hot-plugging management, or even error handling during drive failures. The implications are wide-ranging. Knowing *where* it's utilized will determine the impact.
|
| 47/2 |
2026/08/30 01:16 |
tool |
grepper |
0m
Args: map[Expression:RAID_AUTORUN]
Results: map[Output:include/uapi/linux/raid/md_u.h-38-#define GET_DISK_INFO _IOR (MD_MAJOR, 0x12, mdu_disk_info_t)
include/uapi/linux/raid/md_u.h:39:#define RAID_AUTORUN _IO (MD_MAJOR, 0x14)
include/uapi/linux/raid/md_u.h-40-#define GET_BITMAP_FILE _IOR (MD_MAJOR, 0x15, mdu_bitmap_file_t)
]
|
| 48/2 |
2026/08/30 01:16 |
llm |
expert |
0m
Model:
Tokens:
input: 40893
output: 23
thoughts: 99
Thoughts: **Investigating the Kernel's Array Run Control**
Okay, so I'm looking at this `md_run` function. It's *defined* in the kernel, but it's not directly called within the standard code flow. Interesting. My initial assessment is that it's only invoked through either `do_md_run`, which is triggered by that `RUN_ARRAY` ioctl, or from the `dm-raid` driver via `dm_ctl_ioctl`. Both of those paths, of course, require the `CAP_SYS_ADMIN` capability. That makes sense from a security standpoint.
But...wait a second, what about sysfs? Is there some backdoor via sysfs that I'm overlooking? Could we potentially manipulate an array's state just by writing to a sysfs attribute and triggering `md_run` indirectly? I need to check the relevant sysfs attribute handlers, probably something like `md_attr_store`, or anything similar that might exist within the module. Let's dig in and see if this is possible. It’s an unlikely avenue, but it's worth checking before I move on.
|
| 49/2 |
2026/08/30 01:16 |
tool |
codesearch-find-references |
0m
Args:
Results: map[References:[map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:array_state_store SourceFile:drivers/md/md.c SourceLine:4724] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:array_state_store SourceFile:drivers/md/md.c SourceLine:4739] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:array_state_store SourceFile:drivers/md/md.c SourceLine:4765] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:autorun_array SourceFile:drivers/md/md.c SourceLine:7249] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:md_ioctl SourceFile:drivers/md/md.c SourceLine:8515] map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:md_setup_drive SourceFile:drivers/md/md-autodetect.c SourceLine:220]] TruncatedOutput:false]
|
| 50/2 |
2026/08/30 01:17 |
llm |
expert |
0m
Model:
Tokens:
input: 41577
output: 36
thoughts: 29
Thoughts: Okay, here's my take on those thoughts, framed as my own mental process, given my expertise:
**Diving into the Data Storage**
Right, `array_state_store` is the function that kicks off a `do_md_run`. That's the key connection. This tells me we're looking at how a specific array's state is being managed and that something related to the MD (likely referring to metadata, or some kind of management run) is happening as a consequence of storing the array data. So, the logical next step for me is to trace what exactly `array_state_store` does. I need to understand its role. What does it handle? Does it perform the store itself, or simply trigger an operation that does? What's its relationship to the lower levels? I want to dig into `array_state_store` specifically to get the whole picture. Let's see how that connection is made...
|
| 51/2 |
2026/08/30 01:17 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/md/md.c Name:array_state_store]
Results: map[SourceCode:4655: static ssize_t
4656: array_state_store(struct mddev *mddev, const char *buf, size_t len)
4657: {
4658: int err = 0;
4659: enum array_state st = match_word(buf, array_states);
4660:
4661: /* No lock dependent actions */
4662: switch (st) {
4663: case suspended: /* not supported yet */
4664: case write_pending: /* cannot be set */
4665: case active_idle: /* cannot be set */
4666: case broken: /* cannot be set */
4667: case bad_word:
4668: return -EINVAL;
4669: case clear:
4670: case readonly:
4671: case inactive:
4672: case read_auto:
4673: if (!mddev->pers || !md_is_rdwr(mddev))
4674: break;
4675: /* write sysfs will not open mddev and opener should be 0 */
4676: err = mddev_set_closing_and_sync_blockdev(mddev, 0);
4677: if (err)
4678: return err;
4679: break;
4680: default:
4681: break;
4682: }
4683:
4684: if (mddev->pers && (st == active || st == clean) &&
4685: mddev->ro != MD_RDONLY) {
4686: /* don't take reconfig_mutex when toggling between
4687: * clean and active
4688: */
4689: spin_lock(&mddev->lock);
4690: if (st == active) {
4691: restart_array(mddev);
4692: clear_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags);
4693: md_wakeup_thread(mddev->thread);
4694: wake_up(&mddev->sb_wait);
4695: } else /* st == clean */ {
4696: restart_array(mddev);
4697: if (!set_in_sync(mddev))
4698: err = -EBUSY;
4699: }
4700: if (!err)
4701: sysfs_notify_dirent_safe(mddev->sysfs_state);
4702: spin_unlock(&mddev->lock);
4703: return err ?: len;
4704: }
4705: err = mddev_lock(mddev);
4706: if (err)
4707: return err;
4708:
4709: switch (st) {
4710: case inactive:
4711: /* stop an active array, return 0 otherwise */
4712: if (mddev->pers)
4713: err = do_md_stop(mddev, 2);
4714: break;
4715: case clear:
4716: err = do_md_stop(mddev, 0);
4717: break;
4718: case readonly:
4719: if (mddev->pers)
4720: err = md_set_readonly(mddev);
4721: else {
4722: mddev->ro = MD_RDONLY;
4723: set_disk_ro(mddev->gendisk, 1);
4724: err = do_md_run(mddev);
4725: }
4726: break;
4727: case read_auto:
4728: if (mddev->pers) {
4729: if (md_is_rdwr(mddev))
4730: err = md_set_readonly(mddev);
4731: else if (mddev->ro == MD_RDONLY)
4732: err = restart_array(mddev);
4733: if (err == 0) {
4734: mddev->ro = MD_AUTO_READ;
4735: set_disk_ro(mddev->gendisk, 0);
4736: }
4737: } else {
4738: mddev->ro = MD_AUTO_READ;
4739: err = do_md_run(mddev);
4740: }
4741: break;
4742: case clean:
4743: if (mddev->pers) {
4744: err = restart_array(mddev);
4745: if (err)
4746: break;
4747: spin_lock(&mddev->lock);
4748: if (!set_in_sync(mddev))
4749: err = -EBUSY;
4750: spin_unlock(&mddev->lock);
4751: } else
4752: err = -EINVAL;
4753: break;
4754: case active:
4755: if (mddev->pers) {
4756: err = restart_array(mddev);
4757: if (err)
4758: break;
4759: clear_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags);
4760: wake_up(&mddev->sb_wait);
4761: err = 0;
4762: } else {
4763: mddev->ro = MD_RDWR;
4764: set_disk_ro(mddev->gendisk, 0);
4765: err = do_md_run(mddev);
4766: }
4767: break;
4768: default:
4769: err = -EINVAL;
4770: break;
4771: }
4772:
4773: if (!err) {
4774: if (mddev->hold_active == UNTIL_IOCTL)
4775: mddev->hold_active = 0;
4776: sysfs_notify_dirent_safe(mddev->sysfs_state);
4777: }
4778: mddev_unlock(mddev);
4779:
4780: if (st == readonly || st == read_auto || st == inactive ||
4781: (err && st == clear))
4782: clear_bit(MD_CLOSING, &mddev->flags);
4783:
4784: return err ?: len;
4785: }
SourceFile:drivers/md/md.c]
|
| 52/2 |
2026/08/30 01:17 |
llm |
expert |
0m
Model:
Tokens:
input: 43721
output: 23
thoughts: 47
Thoughts: **Investigating Access to `array_state_store`**
Okay, so I'm looking at this `array_state_store` attribute and immediately I'm asking myself, who's got write access here? Given that it's a sysfs attribute, my initial instinct, based on past experience with block devices and sysfs, is that this is probably a root-owned thing. The security implications are pretty clear, if any regular user could change this, things could get ugly, fast. Let's see... I'll dive into `md_attr_array_state` and see what the documentation and permissions say. Hopefully, the implementation makes it clear, or at least hints at how access is controlled. Gotta be careful here, any changes require rigorous testing and review.
|
| 53/2 |
2026/08/30 01:17 |
tool |
codesearch-find-references |
0m
Args: map[Name:array_state_store]
Results: map[References:[map[ReferenceKind:takes-address-of ReferencingEntityKind:function ReferencingEntityName:md_attr_store SourceFile:drivers/md/md.c SourceLine:6147] map[ReferenceKind:takes-address-of ReferencingEntityKind:global_variable ReferencingEntityName:md_array_state SourceFile:drivers/md/md.c SourceLine:4787]] TruncatedOutput:false]
|
| 54/2 |
2026/08/30 01:17 |
llm |
expert |
0m
Model:
Tokens:
input: 44086
output: 36
thoughts: 11
Thoughts: Okay, here's my interpretation of that thought process, assuming I'm deep in my domain of expertise:
**Checking `md_array_state`**
Alright, time to dive in. My immediate thought is, "Let's check the `md_array_state`". That's where the rubber meets the road. It's the central point. I need to see what the current status is. This isn't just a casual glance; I'm going to critically examine its values, the data structures within it, and how they relate to the underlying physical storage. I'm looking for anomalies, discrepancies, or anything that doesn't align with the expected behavior of the system, given the current workload and recent operations. `md_array_state` is the heartbeat of this array; I need to diagnose it and check for any issues.
|
| 55/2 |
2026/08/30 01:17 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/md/md.c Name:md_array_state]
Results: map[SourceCode:4786: static struct md_sysfs_entry md_array_state =
4787: __ATTR_PREALLOC(array_state, S_IRUGO|S_IWUSR, array_state_show, array_state_store);
SourceFile:drivers/md/md.c]
|
| 56/2 |
2026/08/30 01:17 |
llm |
expert |
0m
Model:
Tokens:
input: 44405
output: 23
thoughts: 240
Thoughts: **My Analysis of `do_md_run` and User Namespaces**
Okay, so `S_IWUSR` on `do_md_run` is pretty clear: only the owner, typically root, has write access. That locks down the function, whether accessed through ioctl or sysfs. But wait, what about user namespaces? It's a key question, given my expertise in this area.
My understanding is that sysfs isn't mountable within a user namespace unless it's already mounted externally. And even then, the original files are owned by root in the initial namespace, so a user within a user namespace can't write to them. I've encountered that countless times, particularly with complex container deployments. Similarly, device nodes used for ioctl are also root-owned. And `capable(CAP_SYS_ADMIN)` checks the initial namespace, which means it is inaccessible from user namespaces. So, `do_md_run` is pretty well-protected.
Now, what about `md_autodetect_dev`? That’s where things get interesting. A user plugging in a rogue USB drive with a malicious partition table could trigger `md_autodetect_dev`. But, as I recall, it just adds the device to a list. That list is then processed by `autodetect_raid`, which is called during boot from `md_run_setup`. My concern here is whether `autodetect_raid` is called *anywhere else*? If it is, and under the wrong conditions, it could lead to an unintended exploit. That's the vulnerability I need to examine.
|
| 57/2 |
2026/08/30 01:17 |
tool |
codesearch-find-references |
0m
Args: map[Name:autodetect_raid]
Results: map[References:[map[ReferenceKind:calls ReferencingEntityKind:function ReferencingEntityName:md_run_setup SourceFile:drivers/md/md-autodetect.c SourceLine:279]] TruncatedOutput:false]
|
| 58/2 |
2026/08/30 01:17 |
llm |
expert |
0m
Model:
Tokens:
input: 45085
output: 20
thoughts: 60
Thoughts: **Investigating the Autostart of RAID Arrays**
Okay, so the question is, when does this RAID array autostart? My initial hunch is that it's only during the boot process. But wait... is there something else I'm missing? I need to consider `RAID_AUTORUN` ioctl. Is that the key?
Now I need to dive deeper into the kernel code. Specifically, where is this `RAID_AUTORUN` ioctl actually handled? My instincts tell me it's likely within the `md_ioctl`, `blkdev_ioctl`, or perhaps even the `compat_blkdev_ioctl` functions. I need to trace through those functions to pinpoint where this specific functionality is managed and confirm how autostart is controlled. Let's start digging through the source code.
|
| 59/2 |
2026/08/30 01:17 |
tool |
grepper |
0m
Args: map[Expression:RAID_AUTORUN]
Results: map[Output:include/uapi/linux/raid/md_u.h-38-#define GET_DISK_INFO _IOR (MD_MAJOR, 0x12, mdu_disk_info_t)
include/uapi/linux/raid/md_u.h:39:#define RAID_AUTORUN _IO (MD_MAJOR, 0x14)
include/uapi/linux/raid/md_u.h-40-#define GET_BITMAP_FILE _IOR (MD_MAJOR, 0x15, mdu_bitmap_file_t)
]
|
| 60/2 |
2026/08/30 01:17 |
llm |
expert |
0m
Model:
Tokens:
input: 45486
output: 39
thoughts: 347
Thoughts: **Analyzing a Kernel Bug Related to RAID Disk Limits**
Okay, so I'm looking at this kernel bug, and initially, I thought the code in question might have been removed, since I couldn't immediately find its usage in the kernel source. But, hang on, let's double-check `md_autodetect_dev`. Hmm, is there another way the md array assembly gets triggered?
Right, `mdadm` uses ioctls from userspace, opening the device, but that requires root, which isn't the issue. Let's get back to the bug.
The actual issue is a WARNING in `__kvmalloc_node_noprof` because the requested `size` exceeds `INT_MAX`, and `__GFP_NOWARN` isn't set. The size calculation is coming from `array3_size(sizeof(struct md_rdev *), conf->nr_strip_zones, mddev->raid_disks)`. Now, `sizeof(struct md_rdev *)` is 8 bytes, so we're talking about a calculation involving `conf->nr_strip_zones` (the number of unique device sizes in the array) and `mddev->raid_disks` (the number of disks in the array). The key here is that `nr_strip_zones` is at most the number of `raid_disks`. So the entire `size` is at most `8 * raid_disks * raid_disks`.
To hit that `INT_MAX` limit (2147483647), we need `raid_disks * raid_disks > 268435455`, which means `raid_disks` has to be greater than 16383. The question now is: Is there a limit imposed on the `raid_disks` value? I'll need to check the code in `md_add_new_disk` or `md_set_array_info` to figure this out.
|
| 61/2 |
2026/08/30 01:17 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/md/md.c Name:__md_set_array_info]
Results: map[SourceCode:8308: static int __md_set_array_info(struct mddev *mddev, void __user *argp)
8309: {
8310: mdu_array_info_t info;
8311: int err;
8312:
8313: if (!argp)
8314: memset(&info, 0, sizeof(info));
8315: else if (copy_from_user(&info, argp, sizeof(info)))
8316: return -EFAULT;
8317:
8318: if (mddev->pers) {
8319: err = update_array_info(mddev, &info);
8320: if (err)
8321: pr_warn("md: couldn't update array info. %d\n", err);
8322: return err;
8323: }
8324:
8325: if (!list_empty(&mddev->disks)) {
8326: pr_warn("md: array %s already has disks!\n", mdname(mddev));
8327: return -EBUSY;
8328: }
8329:
8330: if (mddev->raid_disks) {
8331: pr_warn("md: array %s already initialised!\n", mdname(mddev));
8332: return -EBUSY;
8333: }
8334:
8335: err = md_set_array_info(mddev, &info);
8336: if (err)
8337: pr_warn("md: couldn't set array info. %d\n", err);
8338:
8339: return err;
8340: }
SourceFile:drivers/md/md.c]
|
| 62/2 |
2026/08/30 01:17 |
llm |
expert |
0m
Model:
Tokens:
input: 46824
output: 38
thoughts: 13
Thoughts: Here's my attempt at summarizing the thought process, tailored for an expert audience:
**Analyzing `md_set_array_info`**
Okay, time to dive into `md_set_array_info`. Let's see... my first thought is to quickly review the context. I'll need to remember the surrounding logic. Where is this function called from? What's the typical workflow? What's the overall architecture of this array management system? Knowing this will help me understand why we're dealing with array info here.
I'll need to carefully consider the potential for race conditions or concurrent access issues here, especially if we have multiple threads or processes interacting with the array metadata. Any locking mechanisms? How robust are they? Does this function correctly handle different scenarios related to array size, device assignments, and the general state of the array?
I'm thinking about edge cases now. Are there any known vulnerabilities related to how this function handles bad input, or potential memory corruption if something goes wrong? Could a malicious actor exploit a flaw in this function?
Also, I'll pay close attention to the data structures this function manipulates. How are they defined? Is there any potential for data structure misalignment? Does the system perform sufficient validation of these data structures? Are there any potential memory leaks or resource management issues?
I should also think about the performance implications. Is this a critical path function? Are there any obvious performance bottlenecks? Can it be optimized? Does it scale well to larger arrays and more complex configurations?
I'll review the code line-by-line, looking for any obvious red flags: buffer overflows, incorrect pointer arithmetic, missing error checks. I'll mentally step through the control flow and consider different scenarios. I'll pay attention to any comments or documentation. Does the existing documentation seem correct? Is it up-to-date?
I anticipate that there are going to be some tricky aspects here, given the inherent complexity of array management. I will have to be meticulous!
|
| 63/2 |
2026/08/30 01:18 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/md/md.c Name:md_set_array_info]
Results: map[SourceCode:7894: /*
7895: * md_set_array_info is used two different ways
7896: * The original usage is when creating a new array.
7897: * In this usage, raid_disks is > 0 and it together with
7898: * level, size, not_persistent,layout,chunksize determine the
7899: * shape of the array.
7900: * This will always create an array with a type-0.90.0 superblock.
7901: * The newer usage is when assembling an array.
7902: * In this case raid_disks will be 0, and the major_version field is
7903: * use to determine which style super-blocks are to be found on the devices.
7904: * The minor and patch _version numbers are also kept incase the
7905: * super_block handler wishes to interpret them.
7906: */
7907: int md_set_array_info(struct mddev *mddev, struct mdu_array_info_s *info)
7908: {
7909: if (info->raid_disks == 0) {
7910: /* just setting version number for superblock loading */
7911: if (info->major_version < 0 ||
7912: info->major_version >= ARRAY_SIZE(super_types) ||
7913: super_types[info->major_version].name == NULL) {
7914: /* maybe try to auto-load a module? */
7915: pr_warn("md: superblock version %d not known\n",
7916: info->major_version);
7917: return -EINVAL;
7918: }
7919: mddev->major_version = info->major_version;
7920: mddev->minor_version = info->minor_version;
7921: mddev->patch_version = info->patch_version;
7922: mddev->persistent = !info->not_persistent;
7923: /* ensure mddev_put doesn't delete this now that there
7924: * is some minimal configuration.
7925: */
7926: mddev->ctime = ktime_get_real_seconds();
7927: return 0;
7928: }
7929: mddev->major_version = MD_MAJOR_VERSION;
7930: mddev->minor_version = MD_MINOR_VERSION;
7931: mddev->patch_version = MD_PATCHLEVEL_VERSION;
7932: mddev->ctime = ktime_get_real_seconds();
7933:
7934: mddev->level = info->level;
7935: mddev->clevel[0] = 0;
7936: mddev->dev_sectors = 2 * (sector_t)info->size;
7937: mddev->raid_disks = info->raid_disks;
7938: /* don't set md_minor, it is determined by which /dev/md* was
7939: * openned
7940: */
7941: if (info->state & (1<<MD_SB_CLEAN))
7942: mddev->resync_offset = MaxSector;
7943: else
7944: mddev->resync_offset = 0;
7945: mddev->persistent = ! info->not_persistent;
7946: mddev->external = 0;
7947:
7948: mddev->layout = info->layout;
7949: if (mddev->level == 0)
7950: /* Cannot trust RAID0 layout info here */
7951: mddev->layout = -1;
7952: mddev->chunk_sectors = info->chunk_size >> 9;
7953:
7954: if (mddev->persistent) {
7955: mddev->max_disks = MD_SB_DISKS;
7956: mddev->flags = 0;
7957: mddev->sb_flags = 0;
7958: }
7959: set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
7960:
7961: mddev->bitmap_info.default_offset = MD_SB_BYTES >> 9;
7962: mddev->bitmap_info.default_space = 64*2 - (MD_SB_BYTES >> 9);
7963: mddev->bitmap_info.offset = 0;
7964:
7965: mddev->reshape_position = MaxSector;
7966:
7967: /*
7968: * Generate a 128 bit UUID
7969: */
7970: get_random_bytes(mddev->uuid, 16);
7971:
7972: mddev->new_level = mddev->level;
7973: mddev->new_chunk_sectors = mddev->chunk_sectors;
7974: mddev->new_layout = mddev->layout;
7975: mddev->delta_disks = 0;
7976: mddev->reshape_backwards = 0;
7977:
7978: return 0;
7979: }
SourceFile:drivers/md/md.c]
|
| 64/2 |
2026/08/30 01:18 |
llm |
expert |
0m
Model:
Tokens:
input: 48788
output: 46
thoughts: 91
Thoughts: **My Concerns Regarding `mddev->raid_disks`**
Okay, let's see. My initial thought here is how the `mddev->raid_disks` member is populated. The code seems to be setting it directly from `info->raid_disks`. That seems straightforward enough, but my immediate question is, where is `info->raid_disks` coming from? Specifically, is there *any* validation being done on `info->raid_disks` before it's used? I need to be sure the value is sane.
Digging deeper... I'm looking at `md_set_array_info` and I'm not seeing any explicit checks on `info->raid_disks` to ensure it stays within reasonable bounds. That's a red flag. We definitely need some sort of upper bound check here.
Wait a second… Looking at the type definition of `info->raid_disks` in `mdu_array_info_s`, it's just an `int`. Okay, we *definitely* need to validate this to avoid unexpected values that would lead to memory corruption or undefined behavior.
|
| 65/2 |
2026/08/30 01:18 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:include/uapi/linux/raid/md_u.h Name:mdu_array_info_s]
Results: map[SourceCode: 73: typedef struct mdu_array_info_s {
74: /*
75: * Generic constant information
76: */
77: int major_version;
78: int minor_version;
79: int patch_version;
80: unsigned int ctime;
81: int level;
82: int size;
83: int nr_disks;
84: int raid_disks;
85: int md_minor;
86: int not_persistent;
87:
88: /*
89: * Generic state information
90: */
91: unsigned int utime; /* 0 Superblock update time */
92: int state; /* 1 State bits (clean, ...) */
93: int active_disks; /* 2 Number of currently active disks */
94: int working_disks; /* 3 Number of working disks */
95: int failed_disks; /* 4 Number of failed disks */
96: int spare_disks; /* 5 Number of spare disks */
97:
98: /*
99: * Personality information
100: */
101: int layout; /* 0 the array's physical layout */
102: int chunk_size; /* 1 chunk size in bytes */
103:
104: } mdu_array_info_t;
SourceFile:include/uapi/linux/raid/md_u.h]
|
| 66/2 |
2026/08/30 01:18 |
llm |
expert |
0m
Model:
Tokens:
input: 49623
output: 37
thoughts: 145
Thoughts: **Analyzing the Vulnerability**
Okay, so `raid_disks` is definitely an integer. That's the starting point. And a user with `CAP_SYS_ADMIN` can potentially input a massive value for it, like a billion. That's... interesting. The issue is that this huge number could cause `array3_size` to either overflow or produce a result larger than `INT_MAX`. That triggers a warning within `__kvmalloc_node_noprof`.
But hold on, since `CAP_SYS_ADMIN` is needed, this isn't exploitable from your standard unprivileged processes or user namespaces. That's good from a security perspective. It limits the attack surface significantly. However, we're not quite done.
I need to think carefully here. Is there *any* other way to manipulate `raid_disks` besides this direct method? Is this the *only* avenue of control? What about that `sysfs raid_disks` attribute? I need to check if that provides an alternative, and potentially, easier way of passing such a large value without requiring `CAP_SYS_ADMIN`. That's where I need to focus my efforts.
|
| 67/2 |
2026/08/30 01:18 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/md/md.c Name:raid_disks_store]
Results: map[SourceCode:4416: static ssize_t
4417: raid_disks_store(struct mddev *mddev, const char *buf, size_t len)
4418: {
4419: unsigned int n;
4420: unsigned int noio_flags;
4421: int err;
4422:
4423: err = kstrtouint(buf, 10, &n);
4424: if (err < 0)
4425: return err;
4426:
4427: err = mddev_suspend_and_lock(mddev);
4428: if (err)
4429: return err;
4430: noio_flags = memalloc_noio_save();
4431: if (mddev->pers) {
4432: if (n != mddev->raid_disks)
4433: err = update_raid_disks(mddev, n);
4434: } else if (mddev->reshape_position != MaxSector) {
4435: struct md_rdev *rdev;
4436: int olddisks = mddev->raid_disks - mddev->delta_disks;
4437:
4438: err = -EINVAL;
4439: rdev_for_each(rdev, mddev) {
4440: if (olddisks < n &&
4441: rdev->data_offset < rdev->new_data_offset)
4442: goto out_unlock;
4443: if (olddisks > n &&
4444: rdev->data_offset > rdev->new_data_offset)
4445: goto out_unlock;
4446: }
4447: err = 0;
4448: mddev->delta_disks = n - olddisks;
4449: mddev->raid_disks = n;
4450: mddev->reshape_backwards = (mddev->delta_disks < 0);
4451: } else
4452: mddev->raid_disks = n;
4453: out_unlock:
4454: memalloc_noio_restore(noio_flags);
4455: mddev_unlock_and_resume(mddev);
4456: return err ? err : len;
4457: }
SourceFile:drivers/md/md.c]
|
| 68/2 |
2026/08/30 01:18 |
llm |
expert |
0m
Model:
Tokens:
input: 50744
output: 36
thoughts: 1595
Thoughts: **Analysis of the RAID Disk Allocation Vulnerability**
Okay, so I'm looking at this kernel code and thinking about how it could be exploited. `raid_disks_store` reads an unsigned integer, `n`, and sets `mddev->raid_disks` to that value. The concerning thing is the lack of an upper bound check on `n`. My initial thought was, could this be triggered through a malicious filesystem? Nope, MD is a block device layer, not a filesystem.
Then I considered a malicious USB device. If a USB device with a crafted partition table sets the `ADDPART_FLAG_RAID` flag, `md_autodetect_dev` is called. However, that function just adds the device to a list, which is then processed during boot by `autodetect_raid`. So, plugging in a USB device *after* boot wouldn't trigger that particular path.
But wait a minute... what about `mdadm` and udev rules? Does `mdadm` run automatically when a new block device appears? Yes, udev rules typically run `mdadm --incremental`. If `mdadm` runs, it will read the superblock from the device and try to assemble an array. If the superblock contains a large `raid_disks` value, `mdadm` will pass it to the kernel using the `SET_ARRAY_INFO` ioctl.
Now, `mdadm` runs as root through udev. That's the vector. A malicious USB device could provide a crafted MD superblock. `mdadm` reads and parses this, calls `SET_ARRAY_INFO` with a large `raid_disks` value. I need to check whether `mdadm` validates this value.
From what I understand, `mdadm` is a user-space tool. However, it passes a large `raid_disks` value to the kernel, and the kernel then processes it. If it accepts this large value, `RUN_ARRAY` is triggered, and a warning is printed. The warning is just a `WARN_ON_ONCE` and returns `NULL`. If `kvzalloc` also returns `NULL`, then `create_strip_zones` returns `-ENOMEM`. That's the vulnerability.
So, is it exploitable? No, it's just a warning. `WARN_ON_ONCE` doesn't crash the kernel in a production environment (unless `panic_on_warn` is set, which is not the default). It just returns `NULL`, and the allocation failure is handled gracefully.
Could it cause a Denial of Service (DoS)? A warning doesn't typically cause a DoS. It just prints a message and continues. However, what if `array3_size` overflows? If it overflows to `SIZE_MAX`, `kvzalloc` will trigger the warning and return `NULL`. What if it doesn't overflow to `SIZE_MAX`, but overflows to `INT_MAX`? Well, `__kvmalloc_node_noprof` checks if `size > INT_MAX`, and if that happens, it throws a warning and returns `NULL`. What if `size <= INT_MAX`? In that case, `kvzalloc` will try to allocate up to 2GB of memory! If this succeeds, it's a huge allocation. If it fails, it could trigger the OOM killer, which *could* cause a DoS. Though `GFP_KERNEL` allocations this large may simply fail or trigger OOM in either case.
Again, `mdadm` is a user-space tool, and the large `raid_disks` value comes from the superblock, so can a malicious USB device cause OOM? If `raid_disks` is, say, 16000, then `8 * 16000 * 16000 = 2048000000` bytes (approx 2GB). This is < INT_MAX, so `kvzalloc` will try to allocate 2GB. `kvzalloc` uses `vmalloc` for large allocations. `vmalloc` can allocate 2GB *if* there's sufficient virtual and physical memory. If memory is insufficient, it *will* trigger OOM, and that could be a DoS via a malicious USB device (Peripheral Trigger).
Let's check if `mdadm` has any limits. I haven't got the `mdadm` source here, but normally, these are limited. The kernel bug is that the kernel doesn't validate `raid_disks` and allows large allocations.
The bug report mentions `WARNING: mm/slub.c:6908 at __kvmalloc_node_noprof`,
|
| 69/2 |
2026/08/30 01:18 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/md/md.c Name:md_ioctl_valid]
Results: map[SourceCode:8267: static inline int md_ioctl_valid(unsigned int cmd)
8268: {
8269: switch (cmd) {
8270: case GET_ARRAY_INFO:
8271: case GET_DISK_INFO:
8272: case RAID_VERSION:
8273: return 0;
8274: case ADD_NEW_DISK:
8275: case GET_BITMAP_FILE:
8276: case HOT_ADD_DISK:
8277: case HOT_REMOVE_DISK:
8278: case RESTART_ARRAY_RW:
8279: case RUN_ARRAY:
8280: case SET_ARRAY_INFO:
8281: case SET_BITMAP_FILE:
8282: case SET_DISK_FAULTY:
8283: case STOP_ARRAY:
8284: case STOP_ARRAY_RO:
8285: case CLUSTERED_DISK_NACK:
8286: if (!capable(CAP_SYS_ADMIN))
8287: return -EACCES;
8288: return 0;
8289: default:
8290: return -ENOTTY;
8291: }
8292: }
SourceFile:drivers/md/md.c]
|
| 70/2 |
2026/08/30 01:18 |
llm |
expert |
0m
Model:
Tokens:
input: 53769
output: 36
thoughts: 71
Thoughts: **My Assessment of Capability Restrictions and Device Mapper Ioctls**
Okay, so I'm thinking about the implications of capability checks here. It's clear that `capable(CAP_SYS_ADMIN)` is being employed. And more importantly, this is explicitly scoped to the *initial* user namespace. That's good, because it means that your garden-variety unprivileged user, and even those operating within a user namespace, can't just waltz in and trigger this functionality directly via an `ioctl`. That's the expected behavior, the intended security posture.
But then my mind drifts to the specific case of `dm-raid`. I need to consider it specifically, right? How does device mapper play into this, what security considerations do those ioctls have? It makes sense to me that they're likely restricted in a similar fashion. And yeah, it is the case, device mapper ioctls are *also* gated behind `CAP_SYS_ADMIN` within that initial namespace. Okay, that's reassuring. I was right to think about the relation between the capability restrictions and device mapper, and this strengthens my understanding of the system's security boundaries.
|
| 71/2 |
2026/08/30 01:18 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/md/dm-ioctl.c Name:ctl_ioctl]
Results: map[SourceCode:2159: static int ctl_ioctl(struct file *file, uint command, struct dm_ioctl __user *user)
2160: {
2161: int r = 0;
2162: int ioctl_flags;
2163: int param_flags;
2164: unsigned int cmd;
2165: struct dm_ioctl *param;
2166: ioctl_fn fn = NULL;
2167: size_t input_param_size;
2168: struct dm_ioctl param_kernel;
2169:
2170: /* only root can play with this */
2171: if (!capable(CAP_SYS_ADMIN))
2172: return -EACCES;
2173:
2174: if (_IOC_TYPE(command) != DM_IOCTL)
2175: return -ENOTTY;
2176:
2177: cmd = _IOC_NR(command);
2178:
2179: /*
2180: * Check the interface version passed in. This also
2181: * writes out the kernel's interface version.
2182: */
2183: r = check_version(cmd, user, ¶m_kernel);
2184: if (r)
2185: return r;
2186:
2187: /*
2188: * Nothing more to do for the version command.
2189: */
2190: if (cmd == DM_VERSION_CMD)
2191: return 0;
2192:
2193: fn = lookup_ioctl(cmd, &ioctl_flags);
2194: if (!fn) {
2195: DMERR("dm_ctl_ioctl: unknown command 0x%x", command);
2196: return -ENOTTY;
2197: }
2198:
2199: /*
2200: * Copy the parameters into kernel space.
2201: */
2202: r = copy_params(user, ¶m_kernel, ioctl_flags, ¶m, ¶m_flags);
2203:
2204: if (r)
2205: return r;
2206:
2207: input_param_size = param->data_size;
2208: r = validate_params(cmd, param);
2209: if (r)
2210: goto out;
2211:
2212: param->data_size = offsetof(struct dm_ioctl, data);
2213: r = fn(file, param, input_param_size);
2214:
2215: if (unlikely(param->flags & DM_BUFFER_FULL_FLAG) &&
2216: unlikely(ioctl_flags & IOCTL_FLAGS_NO_PARAMS))
2217: DMERR("ioctl %d tried to output some data but has IOCTL_FLAGS_NO_PARAMS set", cmd);
2218:
2219: if (!r && ioctl_flags & IOCTL_FLAGS_ISSUE_GLOBAL_EVENT)
2220: dm_issue_global_event();
2221:
2222: /*
2223: * Copy the results back to userland.
2224: */
2225: if (!r && copy_to_user(user, param, param->data_size))
2226: r = -EFAULT;
2227:
2228: out:
2229: free_params(param, input_param_size, param_flags);
2230: return r;
2231: }
SourceFile:drivers/md/dm-ioctl.c]
|
| 72/2 |
2026/08/30 01:18 |
llm |
expert |
0m
Model:
Tokens:
input: 55159
output: 40
thoughts: 1259
Thoughts: **Analysis of the RAID Array Superblock Vulnerability**
Okay, so I've been digging into this. The initial thought, as usual, is to consider how this could be triggered. It looks like the `capable(CAP_SYS_ADMIN)` check is present, just as I'd suspected. The key here is an unprivileged user space component that gets tricked. `mdadm` via udev seems like the likely candidate, right? If someone plugs in a USB drive with a carefully crafted `md` superblock, udev runs `mdadm -I`. `mdadm` reads that superblock.
The real question is, does `mdadm` validate the `raid_disks` value it reads? Let's check the `mdadm` source code. Bingo, `raid_disks` *is* read from the superblock. Now, for the v1.x superblocks, it's a 32-bit integer. If `mdadm` *doesn't* reject a massive `raid_disks` value, it'll pass it to the kernel via `SET_ARRAY_INFO` or `ADD_NEW_DISK`, eventually calling `RUN_ARRAY`. This is where the warning and the memory allocation failure happen.
Initially, my concern was the allocation failure, but it seemed to be manageable since it's only a warning and an allocation failure. Maybe it could lead to OOM and a DoS, which is what Syzkaller would be looking for. But wait a minute... I remember seeing the size check.
Ah, yes! If `size > INT_MAX`, it triggers a `WARN_ON_ONCE` and immediately returns `NULL`. It *never* attempts the allocation in this case.
```c
/* Don't even allow crazy sizes */
if (unlikely(size > INT_MAX)) {
WARN_ON_ONCE(!(flags & __GFP_NOWARN));
return NULL;
}
```
So it simply WARNs and returns NULL if the `size` is greater than `INT_MAX`, and no memory allocation is even attempted. Now, what if `size <= INT_MAX`? Then up to 2GB is allocated. If it fails, `NULL` is returned. If it succeeds, 2GB is allocated. Okay, is there memory corruption? Definitely not. Therefore, I can rule out that it is exploitable.
So it's not exploitable, but is it a DoS? A warning alone isn't a DoS in a production environment. Allocating up to 2GB could cause memory pressure. Though, it's not a permanent leak. It is freed on error or array stop. The DoS impact is very low, but it could trigger the OOM killer. Though, the bug report *specifically* shows the warning being triggered, and the warning *is* the bug itself. It's a bug, so in Syzkaller's view it's a DoS.
But then I had to go back to the prompt, and it says: "If the unexpected condition is also properly handled by the normal control flow...these won't cause denial-of-service."
Here, the condition IS handled:
```c
if (unlikely(size > INT_MAX)) {
WARN_ON_ONCE(!(flags & __GFP_NOWARN));
return NULL;
}
```
It returns `NULL`, and the caller correctly handles the `NULL` return:
```c
conf->devlist = kvzalloc(array3_size(sizeof(struct md_rdev *),
conf->nr_strip_zones,
mddev->raid_disks),
GFP_KERNEL);
if (!conf->devlist)
goto abort;
```
It's properly handled by the normal control flow. Therefore, it will *not* cause denial-of-service. The only consequence is a failed array assembly. So, Denial of Service is False.
Let's review the dimensions:
* **Exploitable: False.**
* **Denial of Service: False.** The warning is handled, and `NULL` is returned and also handled by the caller.
* **Accessible From Unprivileged Processes: False.** Requires `CAP_SYS_ADMIN`.
* **Accessible From User Namespaces: False.** Requires `CAP_SYS_ADMIN` in the initial namespace.
* **VM Guest Trigger: False.**
* **VM Host Trigger in The Confidential Computing Context: False.**
* **Ethernet Network Trigger: False.**
* **Other Remote Trigger: False.**
* **Peripheral Trigger: True.** A malicious USB device with a crafted `md` superblock could trigger this
|
| 73/2 |
2026/08/30 01:19 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/md/md-autodetect.c Name:autodetect_raid]
Results: map[SourceCode: 259: static void __init autodetect_raid(void)
260: {
261: /*
262: * Since we don't want to detect and use half a raid array, we need to
263: * wait for the known devices to complete their probing
264: */
265: printk(KERN_INFO "md: Waiting for all devices to be available before autodetect\n");
266: printk(KERN_INFO "md: If you don't use raid, use raid=noautodetect\n");
267:
268: wait_for_device_probe();
269: md_autostart_arrays(raid_autopart);
270: }
SourceFile:drivers/md/md-autodetect.c]
|
| 74/2 |
2026/08/30 01:19 |
llm |
expert |
0m
Model:
Tokens:
input: 57715
output: 42
thoughts: 82
Thoughts: **Vulnerability Assessment: Autodetect RAID on Boot**
Okay, so `autodetect_raid` is embedded right within the `__init__` function. That means it only runs once, at boot, which is a key observation. If a bad actor were to introduce a malicious USB device before the system even finishes booting, then this `autodetect_raid` function *could* be triggered by that device. The implications of that could be significant, meaning this clearly constitutes a Peripheral Trigger.
But wait, I need to dig deeper. My concern right now is the relationship of `md_autostart_arrays` and the kernel. Does `md_autostart_arrays` have the ability to read the superblock from the kernel? It's essential to understand how it interacts with the kernel to fully assess the risk. I need to investigate the functionality of `md_autostart_arrays` right away.
|
| 75/2 |
2026/08/30 01:19 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/md/md-autodetect.c Name:md_autostart_arrays]
Results: map[SourceCode:11013: void md_autostart_arrays(int part)
11014: {
11015: struct md_rdev *rdev;
11016: struct detected_devices_node *node_detected_dev;
11017: dev_t dev;
11018: int i_scanned, i_passed;
11019:
11020: i_scanned = 0;
11021: i_passed = 0;
11022:
11023: pr_info("md: Autodetecting RAID arrays.\n");
11024:
11025: mutex_lock(&detected_devices_mutex);
11026: while (!list_empty(&all_detected_devices) && i_scanned < INT_MAX) {
11027: i_scanned++;
11028: node_detected_dev = list_entry(all_detected_devices.next,
11029: struct detected_devices_node, list);
11030: list_del(&node_detected_dev->list);
11031: dev = node_detected_dev->dev;
11032: kfree(node_detected_dev);
11033: mutex_unlock(&detected_devices_mutex);
11034: rdev = md_import_device(dev,0, 90);
11035: mutex_lock(&detected_devices_mutex);
11036: if (IS_ERR(rdev))
11037: continue;
11038:
11039: if (test_bit(Faulty, &rdev->flags))
11040: continue;
11041:
11042: set_bit(AutoDetected, &rdev->flags);
11043: list_add(&rdev->same_set, &pending_raid_disks);
11044: i_passed++;
11045: }
11046: mutex_unlock(&detected_devices_mutex);
11047:
11048: pr_debug("md: Scanned %d and added %d devices.\n", i_scanned, i_passed);
11049:
11050: autorun_devices(part);
11051: }
SourceFile:drivers/md/md.c]
|
| 76/2 |
2026/08/30 01:19 |
llm |
expert |
0m
Model:
Tokens:
input: 58698
output: 36
thoughts: 23
Thoughts: Here's my summary, as though I'm thinking through this process:
**Diving into `md_import_device`**
Okay, so the task at hand is definitely `md_import_device`. Seems like a critical entry point to understanding the storage device's current status and potential integrity, likely pulling crucial metadata. My initial thought is to zero in on the core of this function. Let's start with the superblock, that's almost always the logical starting point for understanding a filesystem or RAID setup. I'm going to carefully review how `md_import_device` interacts with it. This probably means understanding the superblock's structure, which fields are read, and the sanity checks applied to validate its contents. I'll need to figure out what data is crucial to the import process, and what it does if something is wrong.
|
| 77/2 |
2026/08/30 01:19 |
tool |
codesearch-definition-source |
0m
Args: map[ContextFile:drivers/md/md.c Name:md_import_device]
Results: map[SourceCode:3820: /*
3821: * Import a device. If 'super_format' >= 0, then sanity check the superblock
3822: *
3823: * mark the device faulty if:
3824: *
3825: * - the device is nonexistent (zero size)
3826: * - the device has no valid superblock
3827: *
3828: * a faulty rdev _never_ has rdev->sb set.
3829: */
3830: static struct md_rdev *md_import_device(dev_t newdev, int super_format, int super_minor)
3831: {
3832: struct md_rdev *rdev;
3833: sector_t size;
3834: int err;
3835:
3836: rdev = kzalloc_obj(*rdev);
3837: if (!rdev)
3838: return ERR_PTR(-ENOMEM);
3839:
3840: err = md_rdev_init(rdev);
3841: if (err)
3842: goto out_free_rdev;
3843: err = alloc_disk_sb(rdev);
3844: if (err)
3845: goto out_clear_rdev;
3846:
3847: rdev->bdev_file = bdev_file_open_by_dev(newdev,
3848: BLK_OPEN_READ | BLK_OPEN_WRITE,
3849: super_format == -2 ? &claim_rdev : rdev, NULL);
3850: if (IS_ERR(rdev->bdev_file)) {
3851: pr_warn("md: could not open device unknown-block(%u,%u).\n",
3852: MAJOR(newdev), MINOR(newdev));
3853: err = PTR_ERR(rdev->bdev_file);
3854: goto out_clear_rdev;
3855: }
3856: rdev->bdev = file_bdev(rdev->bdev_file);
3857:
3858: kobject_init(&rdev->kobj, &rdev_ktype);
3859:
3860: size = bdev_nr_bytes(rdev->bdev) >> BLOCK_SIZE_BITS;
3861: if (!size) {
3862: pr_warn("md: %pg has zero or unknown size, marking faulty!\n",
3863: rdev->bdev);
3864: err = -EINVAL;
3865: goto out_blkdev_put;
3866: }
3867:
3868: if (super_format >= 0) {
3869: err = super_types[super_format].
3870: load_super(rdev, NULL, super_minor);
3871: if (err == -EINVAL) {
3872: pr_warn("md: %pg does not have a valid v%d.%d superblock, not importing!\n",
3873: rdev->bdev,
3874: super_format, super_minor);
3875: goto out_blkdev_put;
3876: }
3877: if (err < 0) {
3878: pr_warn("md: could not read %pg's sb, not importing!\n",
3879: rdev->bdev);
3880: goto out_blkdev_put;
3881: }
3882: }
3883:
3884: return rdev;
3885:
3886: out_blkdev_put:
3887: fput(rdev->bdev_file);
3888: out_clear_rdev:
3889: md_rdev_clear(rdev);
3890: out_free_rdev:
3891: kfree(rdev);
3892: return ERR_PTR(err);
3893: }
SourceFile:drivers/md/md.c]
|
| 78/2 |
2026/08/30 01:19 |
llm |
expert |
0m
Model:
Tokens:
input: 60090
output: 66
thoughts: 1040
Thoughts: **Analysis of the RAID Superblock Vulnerability**
Okay, let's break this down. My initial thought process went like this: the `super_types[super_format].load_super` function reads the RAID superblock, which is the starting point. Then, `autorun_devices` groups devices by array and calls `autorun_array`. `autorun_array` then calls `md_set_array_info` using the superblock data, and finally executes `do_md_run`. The core of the issue is that a malicious USB device, plugged in at boot, can potentially trigger this via the path: `md_autodetect_dev` -> `md_autostart_arrays` -> `autorun_devices` -> `autorun_array` -> `do_md_run` -> `raid0_run` -> `create_strip_zones`.
While this path is reachable through a peripheral device, and potentially at boot time, it's just a warning. This doesn't seem to lead to any crashes or corruption.
Let's summarize the results: I initially considered the exploitability factors:
* **Exploitable: False** - The vulnerability doesn't seem to lead to any real security breaches.
* **DenialOfService: False** - The worst case scenario is the array fails to start. No DoS condition present.
* **Unprivileged: False** - This can only be triggered by the kernel automatically initializing the device. Unprivileged users can't directly use `md_ioctl`.
* **UserNamespace: False** - The issue isn't related to user namespaces.
* **VMGuestTrigger: False** - This bug appears to be within the host's RAID driver. The prompt asks me to consider if the bug can be triggered from a typical KVM guest, but the RAID driver isn't a paravirtualized feature exposed to a guest. The guest can't send `md_ioctl` commands to the host, as the RAID driver is on the host side. Thus, the guest can't trigger it.
* **VMHostTrigger: False** - Same reason as above, the bug isn't in guest paravirtualized features.
* **NetworkTrigger: False** - Not network related.
* **RemoteTrigger: False** - Not remote.
* **PeripheralTrigger: True** - A malicious USB device with a crafted RAID superblock can trigger it, or potentially udev can auto-assemble such a device.
* **FilesystemTrigger: False** - RAID arrays are block devices, not filesystems.
I double-checked the potential overflow. The function `array3_size(a, b, c)` calculates array size by `size_mul(size_mul(a, b), c)`. This overflows, returning `SIZE_MAX`. Calling `kvzalloc(SIZE_MAX, GFP_KERNEL)` then calls `__kvmalloc_node_noprof(SIZE_MAX, ...)`. Because `SIZE_MAX > INT_MAX`, a warning gets thrown, and `NULL` is returned. The `WARN_ON_ONCE` warning is triggered, which corresponds to what the bug report describes. This is expected.
With the NULL value, `conf->devlist` becomes `NULL`. `create_strip_zones` returns `-ENOMEM`. `raid0_run` returns `-ENOMEM`. `do_md_run` returns `-ENOMEM`. The result is the array fails to start. No memory gets leaked, and there's no memory corruption.
Considering the prompt instructions: "If still unsure err on the side of the bug being non-exploitable/not-accessible." I am reasonably confident it's *not* exploitable in a classic sense, and that it isn't a denial of service. The worst case is that a malicious device can make an array fail to start.
Therefore, using the `set-results` tool, I will set:
* Exploitable: False
* DenialOfService: False
* Unprivileged: False
* UserNamespace: False
* VMGuestTrigger: False
* VMHostTrigger: False
* NetworkTrigger: False
* RemoteTrigger: False
* PeripheralTrigger: True
* FilesystemTrigger: False
My final thought is, can an unprivileged user even trigger this if they create a loop device? No. Unprivileged users *cannot* create loop devices or use `md_ioctl`. `md_ioctl` requires `CAP_SYS_ADMIN` in the initial namespace. Thus the result of Unprivileged being False stands.
|
| 79/2 |
2026/08/30 01:19 |
tool |
set-results |
0m
Args: map[DenialOfService:false Exploitable:false FilesystemTrigger:false NetworkTrigger:false PeripheralTrigger:true RemoteTrigger:false Unprivileged:false UserNamespace:false VMGuestTrigger:false VMHostTrigger:false]
Results: map[DenialOfService:false Exploitable:false FilesystemTrigger:false NetworkTrigger:false PeripheralTrigger:true RemoteTrigger:false Unprivileged:false UserNamespace:false VMGuestTrigger:false VMHostTrigger:false]
|
| 80/2 |
2026/08/30 01:19 |
llm |
expert |
0m
Model:
Tokens:
input: 62259
output: 685
thoughts: 417
Thoughts: **My Final Reasoning**
Okay, the results are in. Now, here's my definitive thinking on this. We're looking at a WARNING situation within `__kvmalloc_node_noprof`. It's triggered when an attempt is made to allocate more memory than `INT_MAX` without the safety net of the `__GFP_NOWARN` flag.
Digging deeper, the culprit is in `create_strip_zones`. It's all about how `array3_size` calculates the size of that `devlist` array. It's using `mddev->raid_disks` and `conf->nr_strip_zones` in the calculation. If we can manipulate `mddev->raid_disks` into being an absurdly large value – perhaps through a carefully crafted md superblock or a malicious `SET_ARRAY_INFO` ioctl – we can easily get that calculated size to blow past `INT_MAX`, or even overflow to `SIZE_MAX`.
The subsequent `kvzalloc` call then dutifully throws the warning and returns `NULL`. The code handles the allocation failure correctly; the array assembly process just aborts and returns `-ENOMEM`.
Here's the kicker: because it's handled, no actual memory corruption or leaks are happening. The system continues to operate normally after the warning. So, in terms of exploitability or a denial-of-service, we're in the clear.
The catch? Triggering this requires the ability to configure an md array with a ridiculous number of disks. The `md_ioctl` commands, such as `SET_ARRAY_INFO` and `RUN_ARRAY`, are strictly guarded by `capable(CAP_SYS_ADMIN)`. This check is in the initial user namespace, which means that unprivileged users or users within user namespaces are blocked from triggering this.
However, a malicious peripheral device becomes interesting. If the system is set to automatically assemble md arrays – either through `md_autodetect_dev` at boot or userspace udev rules running `mdadm` – a crafted md superblock on a device, like a USB drive, could specify an enormous `raid_disks` value, which in turn leads to this warning when the array is assembled.
|
| 81/1 |
2026/08/30 01:19 |
action |
format-explanation |
0m
Results: map[Explanation:**Analysis of the Bug**
The bug report indicates a `WARNING` in `__kvmalloc_node_noprof` at
`mm/slub.c:6908`. This warning is triggered when the kernel attempts to allocate
a memory block larger than `INT_MAX` (2GB) without the `__GFP_NOWARN` flag.
Looking at the call trace, the warning originates from `create_strip_zones` in
`drivers/md/raid0.c`. The vulnerable code attempts to allocate the `devlist`
array using `kvzalloc`:
```c
conf->devlist = kvzalloc(array3_size(sizeof(struct md_rdev *),
conf->nr_strip_zones,
mddev->raid_disks),
GFP_KERNEL);
```
The size of the allocation is calculated using `array3_size`, which multiplies
the three arguments. If `mddev->raid_disks` is extremely large, the
multiplication can exceed `INT_MAX` or overflow to `SIZE_MAX`. When this huge
size is passed to `kvzalloc` (which uses `GFP_KERNEL` and lacks `__GFP_NOWARN`),
the memory allocator explicitly catches the "crazy size", triggers a
`WARN_ON_ONCE`, and safely returns `NULL`.
**Security Impact Assessment**
1. **Exploitable:** **No.** The kernel correctly identifies the oversized
allocation request, issues a warning, and returns `NULL`. The `NULL` return is
properly checked by `create_strip_zones`, which aborts the array assembly and
returns `-ENOMEM`. There is no memory corruption, out-of-bounds access, or
information leak.
2. **Denial of Service (DoS):** **No.** The warning does not halt the system
(unless `panic_on_warn` is enabled, which is not the default in production).
Because the allocation is aborted before any memory is actually consumed, it
does not cause memory exhaustion or OOM conditions. The system continues to
operate normally.
3. **Accessible From Unprivileged Processes / User Namespaces:** **No.**
Configuring and running an md array via `md_ioctl` (e.g., `SET_ARRAY_INFO`,
`RUN_ARRAY`) or sysfs requires `CAP_SYS_ADMIN` in the initial user namespace
(enforced via `capable(CAP_SYS_ADMIN)`). Unprivileged users or users inside a
user namespace cannot reach this code path.
4. **Peripheral Trigger:** **Yes.** A malicious USB device presenting a crafted
md superblock with an artificially huge `raid_disks` value could trigger this
bug. If the system auto-assembles RAID arrays (either via the kernel's boot-time
`md_autodetect_dev` or via userspace udev rules invoking `mdadm`), the crafted
superblock will be parsed and passed to the kernel, triggering the warning.
5. **Other Triggers:** The bug is isolated to the MD (Software RAID) subsystem
and block device layer. It cannot be triggered via network traffic, malicious
filesystems (as it operates at the block layer, not the VFS layer), or from a
typical KVM guest/host context.]
|