KASAN: slab-use-after-free Read in __vb2_queue_cancel (2)

Status: upstream: reported C repro on 2026/08/20 16:05
Subsystems: usb media
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+dd0f06181ab66b93dc00@syzkaller.appspotmail.com
Fix commit: media: em28xx: setup queues before registering V4L2 device
Patched on: [ci-upstream-linux-next-kasan-gce-root ci-upstream-rust-kasan-gce], missing on: [ci-qemu-gce-upstream-auto ci-qemu-native-arm64-kvm ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-qemu2-riscv64 ci-snapshot-upstream-root ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-usb]
First crash: 55d, last: 5d23h
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
e5ced5ea assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ KASAN: slab-use-after-free Read in __vb2_queue_cancel (2) 2026/08/18 01:04 2026/08/18 01:04 2026/08/18 01:54 1e72964b
▶ ▼ Discussions (5)
Title Replies (including bot) Last reply
[syzbot] [media?] KASAN: slab-use-after-free Read in __vb2_queue_cancel (2) 0 (6) 2026/09/10 17:02
[PATCH 2/2] media: em28xx: setup queues before registering V4L2 device 1 (1) 2026/09/10 16:58
[RESEND PATCH 1/2] media: em28xx: adjust initialization order in em28xx_v4l2_init() 5 (5) 2026/09/10 16:56
[RESEND PATCH 2/2] media: em28xx: fix race between em28xx_free_v4l2() and em28xx_v4l2_fini() 3 (3) 2026/09/10 10:12
[PATCH 1/2] media: em28xx: adjust initialization order in em28xx_v4l2_init() 2 (2) 2026/08/25 11:07
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-use-after-free Read in __vb2_queue_cancel prio:high media 19 1 195d 191d 0/29 auto-obsoleted due to no activity on 2026/07/07 06:24
upstream KASAN: slab-out-of-bounds Read in __vb2_queue_cancel media 17 1 289d 285d 0/29 auto-obsoleted due to no activity on 2026/03/24 22:42
▶ ▼ Last patch testing requests (4)
Created Duration User Patch Repo Result
2026/09/10 17:02 2h54m dmantipov@yandex.ru patch https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 50d05c7c76c96b90462f24debacca971d2e86713 OK job log log
2026/09/08 17:29 1h01m dmantipov@yandex.ru patch https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 5acbae5f7eb3d5275120abfe698c394b7325dcec OK job log log
2026/08/25 11:04 28m dmantipov@yandex.ru patch https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 66498c75b4f8017f62d720d9b59675bdf3abce91 OK job log log
2026/08/25 10:05 1m dmantipov@yandex.ru patch https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 66498c75b4f8017f62d720d9b59675bdf3abce91 error job log
▶ ▼ Cause bisection attempts (4)
Created Duration User Patch Repo Result
2026/09/29 23:29 0m bisect upstream error
2026/09/20 16:40 0m bisect upstream error
2026/09/10 06:22 0m bisect upstream error
2026/09/02 02:17 0m bisect upstream error

Sample crash report:
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 UID: 0 PID: 25 Comm: kworker/1:0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026
Workqueue: events request_module_async
RIP: 0010:__wake_up_common+0x9b/0x1f0 kernel/sched/wait.c:105
Code: 02 00 0f 85 5b 01 00 00 48 8b 5b 40 48 8d 43 e8 4c 39 fb 0f 84 b3 00 00 00 48 ba 00 00 00 00 00 fc ff df 48 89 d9 48 c1 e9 03 <80> 3c 11 00 0f 85 18 01 00 00 48 bd 00 00 00 00 00 fc ff df 4c 8b
RSP: 0018:ffffc900001f79a0 EFLAGS: 00010056
RAX: ffffffffffffffe8 RBX: 0000000000000000 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000003 RDI: ffff8880298b5790
RBP: ffff8880298b5790 R08: 0000000000000000 R09: fffff5200003ef2b
R10: 0000000000000003 R11: 00000000000075fb R12: 0000000000000003
R13: 0000000000000000 R14: 0000000000000000 R15: ffff8880298b57d0
FS:  0000000000000000(0000) GS:ffff888123c61000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000557902ace698 CR3: 0000000034273000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 __wake_up_common_lock kernel/sched/wait.c:126 [inline]
 __wake_up+0x31/0x60 kernel/sched/wait.c:147
 __vb2_queue_cancel+0x348/0xe90 drivers/media/common/videobuf2/videobuf2-core.c:2244
 vb2_core_queue_release+0x27/0x190 drivers/media/common/videobuf2/videobuf2-core.c:2677
 vb2_queue_release drivers/media/common/videobuf2/videobuf2-v4l2.c:943 [inline]
 vb2_video_unregister_device drivers/media/common/videobuf2/videobuf2-v4l2.c:1279 [inline]
 vb2_video_unregister_device+0x152/0x2e0 drivers/media/common/videobuf2/videobuf2-v4l2.c:1254
 em28xx_v4l2_init.cold+0xe1a/0x3a18 drivers/media/usb/em28xx/em28xx-video.c:3097
 em28xx_init_extension+0x13a/0x200 drivers/media/usb/em28xx/em28xx-core.c:1248
 request_module_async+0x1e/0x30 drivers/media/usb/em28xx/em28xx-cards.c:3685
 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3387
 process_scheduled_works kernel/workqueue.c:3470 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3551
 kthread+0x373/0x450 kernel/kthread.c:436
 ret_from_fork+0x730/0xd60 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:__wake_up_common+0x9b/0x1f0 kernel/sched/wait.c:105
Code: 02 00 0f 85 5b 01 00 00 48 8b 5b 40 48 8d 43 e8 4c 39 fb 0f 84 b3 00 00 00 48 ba 00 00 00 00 00 fc ff df 48 89 d9 48 c1 e9 03 <80> 3c 11 00 0f 85 18 01 00 00 48 bd 00 00 00 00 00 fc ff df 4c 8b
RSP: 0018:ffffc900001f79a0 EFLAGS: 00010056
RAX: ffffffffffffffe8 RBX: 0000000000000000 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000003 RDI: ffff8880298b5790
RBP: ffff8880298b5790 R08: 0000000000000000 R09: fffff5200003ef2b
R10: 0000000000000003 R11: 00000000000075fb R12: 0000000000000003
R13: 0000000000000000 R14: 0000000000000000 R15: ffff8880298b57d0
FS:  0000000000000000(0000) GS:ffff888123c61000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000557902ace698 CR3: 0000000034273000 CR4: 0000000000350ef0
----------------
Code disassembly (best guess):
   0:	02 00                	add    (%rax),%al
   2:	0f 85 5b 01 00 00    	jne    0x163
   8:	48 8b 5b 40          	mov    0x40(%rbx),%rbx
   c:	48 8d 43 e8          	lea    -0x18(%rbx),%rax
  10:	4c 39 fb             	cmp    %r15,%rbx
  13:	0f 84 b3 00 00 00    	je     0xcc
  19:	48 ba 00 00 00 00 00 	movabs $0xdffffc0000000000,%rdx
  20:	fc ff df
  23:	48 89 d9             	mov    %rbx,%rcx
  26:	48 c1 e9 03          	shr    $0x3,%rcx
* 2a:	80 3c 11 00          	cmpb   $0x0,(%rcx,%rdx,1) <-- trapping instruction
  2e:	0f 85 18 01 00 00    	jne    0x14c
  34:	48 bd 00 00 00 00 00 	movabs $0xdffffc0000000000,%rbp
  3b:	fc ff df
  3e:	4c                   	rex.WR
  3f:	8b                   	.byte 0x8b

Crashes (331):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/30 11:39 upstream 08dbfad3f504 2f52988a .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/25 20:41 upstream 66498c75b4f8 614e416a .config strace log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/23 16:29 upstream 2709dd5ae32f 1e72964b .config strace log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/22 07:30 upstream 26260251022f 1e72964b .config strace log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 16:35 upstream f4cdf7ca9a1f 1e72964b .config strace log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 13:56 upstream f4cdf7ca9a1f 1e72964b .config strace log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 11:57 upstream f4cdf7ca9a1f 1e72964b .config strace log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 09:56 upstream f4cdf7ca9a1f 1e72964b .config strace log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 08:13 upstream f4cdf7ca9a1f 1e72964b .config strace log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 06:41 upstream f4cdf7ca9a1f 1e72964b .config strace log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 05:23 upstream f4cdf7ca9a1f 1e72964b .config strace log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/10/02 08:32 upstream d24e8ac715de 6d32eb1f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: slab-use-after-free Read in __vb2_queue_cancel
2026/10/01 16:45 upstream 551c722f4080 38f7f0d1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root KASAN: slab-use-after-free Read in __vb2_queue_cancel
2026/08/16 15:56 upstream 3eb40771c00a 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce KASAN: slab-use-after-free Read in __vb2_queue_cancel
2026/10/04 20:47 upstream 6addb4f38557 57bbd979 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/24 04:44 upstream 62f4c998b297 0a1606bc .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/24 04:44 upstream 62f4c998b297 0a1606bc .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/23 22:50 upstream fe2ec83746e5 0a1606bc .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/23 09:57 upstream fe2ec83746e5 abce1216 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/22 21:48 upstream c4e9f74da438 3e2106e5 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/22 10:44 upstream f0100363d8c3 e12281bd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/22 07:34 upstream f0100363d8c3 e12281bd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root general protection fault in __vb2_queue_cancel
2026/09/22 01:20 upstream f0100363d8c3 e12281bd .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/21 09:34 upstream 93f51579e7df 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/20 09:13 upstream 518e5b794c06 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/19 18:00 upstream 40288c9206c1 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/19 03:36 upstream ef31d04b6d8a 853b104b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/19 01:02 upstream ef31d04b6d8a 8d7d05f1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/18 08:12 upstream 5dd1818b15d9 8d7d05f1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/17 22:17 upstream 4982d3552a3b 95928915 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/17 05:15 upstream 238650ef6c7c 95928915 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/16 18:26 upstream 9b87fdc9af2f 95928915 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/16 18:19 upstream 9b87fdc9af2f 95928915 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/16 06:41 upstream 9b87fdc9af2f 12a0a44a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/15 20:37 upstream f6e7b42bf05b 81a27d1a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/15 11:08 upstream 587858367581 81a27d1a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/15 10:26 upstream 587858367581 81a27d1a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/15 03:05 upstream 587858367581 924033e8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/14 21:19 upstream 587858367581 924033e8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/14 12:40 upstream 704340f1cd0d 924033e8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/13 16:30 upstream 2f0c1cf72f46 70a60e12 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/13 02:59 upstream cba2348ab114 70a60e12 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/12 11:14 upstream 5225b8eec4c9 70a60e12 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/11 23:49 upstream 3026c6e4f223 b6a5eeb7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/11 13:09 upstream 08df884136f1 b6a5eeb7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/11 01:06 upstream 08df884136f1 1fe56c0a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/10 19:56 upstream 50d05c7c76c9 1fe56c0a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/10 01:48 upstream 50d05c7c76c9 4e8b1cc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/10 01:45 upstream 50d05c7c76c9 4e8b1cc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/09 21:15 upstream 893e11787f78 4e8b1cc6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/09 06:54 upstream 893e11787f78 8387c273 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/08 13:15 upstream 28924df2a08f 243b72f1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/08 10:58 upstream 28924df2a08f 680aa3e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/07 21:30 upstream c297ed90fbba 680aa3e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/07 21:29 upstream c297ed90fbba 680aa3e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/07 15:08 upstream df2908090cda 680aa3e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/07 03:57 upstream df2908090cda 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/09/06 10:58 upstream 1fc5a74b108f 4f7b22a0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
* Struck through repros no longer work on HEAD.