general protection fault in lo_rw_aio

Status: upstream: reported on 2026/04/18 00:02
Subsystems: block
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+cd8a9a308e879a4e2c28@syzkaller.appspotmail.com
First crash: 204d, last: 1h00m
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
c6adaab8 assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ general protection fault in lo_rw_aio 2026/05/23 13:03 2026/05/23 13:03 2026/05/23 14:13 c69befb3
▶ ▼ Discussions (23)
Title Replies (including bot) Last reply
[PATCH v8 2/2] block: wait for inflight requests in bdev_release() 1 (1) 2026/10/18 15:26
[PATCH] loop: Detect write requests that failed to wait for completion. 4 (4) 2026/10/12 08:26
[PATCH v6] loop: Wait for I/O completion in __loop_clr_fd() 1 (1) 2026/10/05 21:06
[PATCH v5 2/2] loop: Perform __loop_clr_fd() from post_release callback. 1 (1) 2026/09/23 05:10
[PATCH v4 2/2] loop: Perform __loop_clr_fd() from run_todo callback. 1 (1) 2026/09/19 10:51
[PATCH v3 2/2] loop: Perform __loop_clr_fd() after disk->open_mutex is dropped. 1 (1) 2026/09/18 15:00
[PATCH v2.1 2/2] loop: Perform __loop_clr_fd() after disk->open_mutex is dropped. 1 (1) 2026/09/18 12:20
[PATCH 2/2] loop: Perform __loop_clr_fd() after disk->open_mutex is dropped. 1 (1) 2026/09/09 10:49
[PATCH v7.1] loop: Fix NULL pointer dereference in lo_rw_aio() 3 (3) 2026/09/04 01:07
[PATCH v7] loop: Fix NULL pointer dereference in lo_rw_aio() 1 (1) 2026/08/28 15:53
[PATCH v3] loop: Fix NULL pointer dereference in lo_rw_aio() 2 (2) 2026/08/28 15:01
[PATCH v5] loop: Fix NULL pointer dereference in lo_rw_aio() 2 (2) 2026/08/23 11:17
[syzbot] Monthly block report (Aug 2026) 0 (1) 2026/08/05 20:32
Re: [linux-next:master] [loop] d908729e74: stress-ng.umount.ops_per_sec 100.0% regression 3 (3) 2026/07/15 16:02
[syzbot] [block?] general protection fault in lo_rw_aio 2 (4) 2026/07/15 16:02
[syzbot] Monthly block report (Jul 2026) 0 (1) 2026/07/05 12:32
[PATCH v4] loop: Fix NULL pointer dereference in lo_rw_aio() 1 (1) 2026/06/07 10:54
Re: [PATCH v3] loop: Fix NULL pointer dereference in lo_rw_aio() 6 (6) 2026/06/02 02:02
[PATCH] block: assign caller-specific lockdep class to disk->open_mutex 2 (2) 2026/05/30 22:50
[PATCH] loop: reject binding to procfs and sysfs files 1 (1) 2026/05/30 13:48
[PATCH] loop: add sync_blockdev() in __loop_clr_fd() to prevent UAF 7 (7) 2026/05/22 11:50
[PATCH v2] loop: Fix NULL pointer dereference by synchronizing lo_release and loop_queue_rq 1 (1) 2026/05/15 01:38
[PATCH] loop: Fix NULL pointer dereference by synchronizing lo_release and loop_queue_rq 1 (1) 2026/05/11 11:43
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream BUG: unable to handle kernel NULL pointer dereference in lo_rw_aio block 10 syz, C 10 549d 558d 29/29 fixed on 2025/07/08 00:33

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000014: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x00000000000000a0-0x00000000000000a7]
CPU: 1 UID: 0 PID: 3305 Comm: kworker/u8:15 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026
Workqueue: loop6 loop_workfn
RIP: 0010:file_inode include/linux/fs.h:1350 [inline]
RIP: 0010:kiocb_start_write include/linux/fs.h:2794 [inline]
RIP: 0010:lo_rw_aio+0xc26/0x1100 drivers/block/loop.c:398
Code: e8 af 0f 02 fc 85 db 0f 84 d8 00 00 00 48 8b 44 24 68 48 8d 98 a0 00 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 12 48 89 df e8 7c 07 75 fc 48 b9 00 00 00 00 00 fc
RSP: 0018:ffffc9000f1ef620 EFLAGS: 00010206
RAX: 0000000000000014 RBX: 00000000000000a0 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000f1ef790 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1004f37465 R12: 0000000000000000
R13: 0000000000001000 R14: 0000000000000000 R15: ffff8880279ba330
FS:  0000000000000000(0000) GS:ffff888124815000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f87b1948c80 CR3: 0000000053e74000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 do_req_filebacked drivers/block/loop.c:430 [inline]
 loop_handle_cmd drivers/block/loop.c:1847 [inline]
 loop_process_work+0x638/0x11d0 drivers/block/loop.c:1882
 process_one_work kernel/workqueue.c:3495 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3578
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3659
 kthread+0x38b/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:file_inode include/linux/fs.h:1350 [inline]
RIP: 0010:kiocb_start_write include/linux/fs.h:2794 [inline]
RIP: 0010:lo_rw_aio+0xc26/0x1100 drivers/block/loop.c:398
Code: e8 af 0f 02 fc 85 db 0f 84 d8 00 00 00 48 8b 44 24 68 48 8d 98 a0 00 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df <80> 3c 08 00 74 12 48 89 df e8 7c 07 75 fc 48 b9 00 00 00 00 00 fc
RSP: 0018:ffffc9000f1ef620 EFLAGS: 00010206
RAX: 0000000000000014 RBX: 00000000000000a0 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000f1ef790 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed1004f37465 R12: 0000000000000000
R13: 0000000000001000 R14: 0000000000000000 R15: ffff8880279ba330
FS:  0000000000000000(0000) GS:ffff888124715000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055755f665cc8 CR3: 00000000390d4000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	e8 af 0f 02 fc       	call   0xfc020fb4
   5:	85 db                	test   %ebx,%ebx
   7:	0f 84 d8 00 00 00    	je     0xe5
   d:	48 8b 44 24 68       	mov    0x68(%rsp),%rax
  12:	48 8d 98 a0 00 00 00 	lea    0xa0(%rax),%rbx
  19:	48 89 d8             	mov    %rbx,%rax
  1c:	48 c1 e8 03          	shr    $0x3,%rax
  20:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
  27:	fc ff df
* 2a:	80 3c 08 00          	cmpb   $0x0,(%rax,%rcx,1) <-- trapping instruction
  2e:	74 12                	je     0x42
  30:	48 89 df             	mov    %rbx,%rdi
  33:	e8 7c 07 75 fc       	call   0xfc7507b4
  38:	48                   	rex.W
  39:	b9 00 00 00 00       	mov    $0x0,%ecx
  3e:	00 fc                	add    %bh,%ah

Crashes (4311):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/11/03 20:07 upstream 05441d697f7f e2d35131 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/11/03 18:02 upstream 05441d697f7f e2d35131 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/11/03 16:13 upstream 6628e7d4c6b2 e2d35131 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/11/03 13:13 upstream 6628e7d4c6b2 e2d35131 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/11/03 12:09 upstream 6628e7d4c6b2 e2d35131 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/11/03 09:18 upstream 6628e7d4c6b2 6969b601 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/11/03 05:15 upstream 6628e7d4c6b2 6969b601 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/11/03 00:50 upstream 6628e7d4c6b2 6969b601 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/11/02 19:09 upstream 6628e7d4c6b2 6969b601 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/11/02 17:29 upstream 6628e7d4c6b2 6969b601 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/11/02 15:03 upstream 6628e7d4c6b2 6969b601 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/11/02 10:21 upstream 6628e7d4c6b2 6969b601 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/11/02 07:47 upstream 6628e7d4c6b2 25a0ae84 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/11/02 06:29 upstream 6628e7d4c6b2 25a0ae84 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/11/02 01:56 upstream cbbddb6b08cc 25a0ae84 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/11/01 21:05 upstream cbbddb6b08cc 25a0ae84 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/11/01 16:14 upstream cbbddb6b08cc 25a0ae84 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/11/01 11:46 upstream e9954f3fbddd 25a0ae84 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/11/01 07:53 upstream e9954f3fbddd 25a0ae84 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/11/01 04:58 upstream e9954f3fbddd 25a0ae84 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/11/01 03:52 upstream e9954f3fbddd 25a0ae84 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/11/01 01:19 upstream e9954f3fbddd 2041d3f8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/31 23:01 upstream e9954f3fbddd 2041d3f8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/31 21:52 upstream 36aad21d50d1 2041d3f8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/31 20:34 upstream 36aad21d50d1 2041d3f8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/31 15:15 upstream 36aad21d50d1 2041d3f8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/31 13:32 upstream 36aad21d50d1 2041d3f8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/31 12:25 upstream 36aad21d50d1 2041d3f8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/31 09:20 upstream 36aad21d50d1 2041d3f8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/31 06:07 upstream bd5c762ac051 0ec395f8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/31 02:59 upstream bd5c762ac051 0ec395f8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/31 00:51 upstream bd5c762ac051 0ec395f8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/30 16:54 upstream d89e1d186ec9 0ec395f8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/30 15:36 upstream d89e1d186ec9 b498adee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/30 13:39 upstream d89e1d186ec9 b498adee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/30 12:10 upstream d89e1d186ec9 b498adee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/30 09:59 upstream d89e1d186ec9 b498adee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/30 08:25 upstream 4dd16e31135e b498adee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/30 07:23 upstream 4dd16e31135e b498adee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/30 06:10 upstream 4dd16e31135e b498adee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/30 05:28 upstream 4dd16e31135e b498adee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/10/30 03:51 upstream 4dd16e31135e b498adee .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/05/22 22:16 upstream 45255ea1ca09 5f091fcc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/04/17 21:49 upstream 43cfbdda5af6 24ecfc1e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs general protection fault in lo_rw_aio
2026/07/02 08:16 linux-next 7de6ae9e1220 27192279 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in lo_rw_aio
2026/04/13 23:56 linux-next 1c7cc4904160 1a086e7c .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root general protection fault in lo_rw_aio
* Struck through repros no longer work on HEAD.