syzbot


WARNING in __alloc_skb (4)

Status: upstream: reported C repro on 2025/08/27 21:55
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+5a2250fd91b28106c37b@syzkaller.appspotmail.com
First crash: 198d, last: 11d
Discussions (3)
Title Replies (including bot) Last reply
[PATCH] [PATCH v2] net: skb: guard kmalloc_reserve() against oversized allocations 2 (2) 2025/09/20 20:19
[syzbot] [mm?] [usb?] WARNING in __alloc_skb (4) 2 (8) 2025/09/20 18:55
[PATCH] net: skb: guard kmalloc_reserve() against oversized allocations 2 (2) 2025/09/20 15:38
Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-6-12 WARNING in __alloc_skb origin:upstream -1 C 10 9d01h 200d 0/1 premoderation: reported C repro on 2025/08/22 06:38
upstream WARNING in __alloc_skb (3) ppp -1 C 2 764d 764d 25/29 fixed on 2024/03/29 01:33
upstream WARNING in __alloc_skb arm-msm net -1 C error 24 1827d 1839d 20/29 fixed on 2021/04/09 19:46
linux-6.1 WARNING in __alloc_skb origin:upstream -1 C done 2 852d 853d 3/3 fixed on 2023/12/11 10:30
upstream WARNING in __alloc_skb (2) ppp -1 C done 2 835d 849d 25/29 fixed on 2024/01/20 21:18
linux-5.15 WARNING in __alloc_skb origin:upstream -1 syz 1 153d 239d 0/3 auto-obsoleted due to no activity on 2026/01/16 10:48
Last patch testing requests (8)
Created Duration User Patch Repo Result
2025/12/21 05:07 31m retest repro linux-next report log
2025/12/21 04:58 24m retest repro linux-next report log
2025/10/12 04:13 25m retest repro linux-next report log
2025/09/20 18:55 25m kriish.sharma2006@gmail.com patch linux-next report log
2025/09/20 10:59 26m kriish.sharma2006@gmail.com patch linux-next OK log
2025/09/20 02:56 26m hdanton@sina.com patch linux-next OK log
2025/09/20 00:43 25m hdanton@sina.com patch linux-next report log
2025/09/19 16:04 17m kriish.sharma2006@gmail.com https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/ 7fa4d8dc380f report log

Sample crash report:
------------[ cut here ]------------
1
WARNING: mm/page_alloc.c:5226 at __alloc_frozen_pages_noprof+0x23ea/0x2ba0 mm/page_alloc.c:5226, CPU#2: ksoftirqd/2/23
Modules linked in:
CPU: 2 UID: 0 PID: 23 Comm: ksoftirqd/2 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:__alloc_frozen_pages_noprof+0x23ea/0x2ba0 mm/page_alloc.c:5226
Code: 00 45 31 c9 49 83 bc 24 70 05 00 00 00 4c 89 4c 24 50 0f 85 5f f8 ff ff c6 44 24 10 00 e9 f3 ea ff ff c6 05 f4 ad 5a 0e 01 90 <0f> 0b 90 e9 69 df ff ff 83 7c 24 40 03 41 bc 04 00 00 00 7f 06 41
RSP: 0018:ffffc9000061f4a0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000014 RDI: 0000000000060820
RBP: 0000000000000014 R08: 0000000000000005 R09: 0000000000000009
R10: 0000000000000014 R11: 0000000000000000 R12: 0000000000060820
R13: 1ffff920000c3ee3 R14: 0000000000000014 R15: 1ffff920000c3ead
FS:  0000000000000000(0000) GS:ffff8880d6547000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000565393821da8 CR3: 0000000038133000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2484
 ___kmalloc_large_node+0x104/0x150 mm/slub.c:5160
 __kmalloc_large_node_noprof+0x1c/0x70 mm/slub.c:5191
 __do_kmalloc_node mm/slub.c:5207 [inline]
 __kmalloc_node_track_caller_noprof+0x5c7/0x850 mm/slub.c:5327
 kmalloc_pfmemalloc net/core/skbuff.c:594 [inline]
 kmalloc_reserve+0x2b7/0x350 net/core/skbuff.c:644
 __alloc_skb+0x185/0x710 net/core/skbuff.c:713
 __netdev_alloc_skb+0x7a/0x960 net/core/skbuff.c:775
 __netdev_alloc_skb_ip_align include/linux/skbuff.h:3505 [inline]
 rx_submit+0xfe/0xd50 drivers/net/usb/usbnet.c:512
 rx_alloc_submit+0xd3/0x150 drivers/net/usb/usbnet.c:1558
 usbnet_bh+0xd08/0x1050 drivers/net/usb/usbnet.c:1634
 process_one_work+0x9d7/0x1920 kernel/workqueue.c:3275
 process_scheduled_works kernel/workqueue.c:3358 [inline]
 bh_worker+0x634/0x880 kernel/workqueue.c:3661
 workqueue_softirq_action+0x142/0x1a0 kernel/workqueue.c:3689
 tasklet_action+0x14/0x70 kernel/softirq.c:952
 handle_softirqs+0x1eb/0x9e0 kernel/softirq.c:622
 run_ksoftirqd kernel/softirq.c:1063 [inline]
 run_ksoftirqd+0x38/0x60 kernel/softirq.c:1055
 smpboot_thread_fn+0x3d3/0xaa0 kernel/smpboot.c:160
 kthread+0x370/0x450 kernel/kthread.c:467
 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (8):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/27 09:21 upstream 3f4a08e64442 a2f13f71 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in __alloc_skb
2025/08/23 21:47 linux-next 7fa4d8dc380f bf27483f .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in __alloc_skb
2025/10/28 21:33 upstream fd57572253bc fd2207e7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 WARNING in __alloc_skb
2025/09/28 03:20 linux-next 262858079afd 001c9061 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in __alloc_skb
2025/09/16 01:40 linux-next 590b221ed425 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in __alloc_skb
2025/09/06 06:37 linux-next be5d4872e528 d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in __alloc_skb
2025/09/02 06:00 linux-next 7fa4d8dc380f 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in __alloc_skb
2025/08/27 06:38 linux-next 7fa4d8dc380f e12e5ba4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in __alloc_skb
* Struck through repros no longer work on HEAD.