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

Status: upstream: reported syz repro on 2026/08/20 16:05
Subsystems: media
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+dd0f06181ab66b93dc00@syzkaller.appspotmail.com
First crash: 5d05h, last: 12h17m
▶ ▼ ✨ 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 (1)
Title Replies (including bot) Last reply
[syzbot] [media?] KASAN: slab-use-after-free Read in __vb2_queue_cancel (2) 0 (1) 2026/08/20 16:05
▶ ▼ 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 145d 141d 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 239d 235d 0/29 auto-obsoleted due to no activity on 2026/03/24 22:42

Sample crash report:
 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>
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 UID: 0 PID: 6072 Comm: kworker/0:6 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Workqueue: events request_module_async
RIP: 0010:__wake_up_common+0x9b/0x1f0 kernel/sched/wait.c:104
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:ffffc900038df9c0 EFLAGS: 00010056
RAX: ffffffffffffffe8 RBX: 0000000000000000 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000003 RDI: ffff88807c4bd790
RBP: ffff88807c4bd790 R08: 0000000000000000 R09: fffff5200071bf2f
R10: 0000000000000003 R11: 00000000000075ab R12: 0000000000000003
R13: 0000000000000000 R14: 0000000000000000 R15: ffff88807c4bd7d0
FS:  0000000000000000(0000) GS:ffff888123bcc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc0cf7ab68c CR3: 0000000076e05000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 __wake_up_common_lock kernel/sched/wait.c:125 [inline]
 __wake_up+0x31/0x60 kernel/sched/wait.c:146
 __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+0xa23/0x1940 kernel/workqueue.c:3322
 process_scheduled_works kernel/workqueue.c:3405 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
 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:104
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:ffffc900038df9c0 EFLAGS: 00010056
RAX: ffffffffffffffe8 RBX: 0000000000000000 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000003 RDI: ffff88807c4bd790
RBP: ffff88807c4bd790 R08: 0000000000000000 R09: fffff5200071bf2f
R10: 0000000000000003 R11: 00000000000075ab R12: 0000000000000003
R13: 0000000000000000 R14: 0000000000000000 R15: ffff88807c4bd7d0
FS:  0000000000000000(0000) GS:ffff888123bcc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc0cf7ab68c CR3: 0000000076e05000 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 (48):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
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
2026/08/16 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
2026/08/21 09:05 upstream 818bebeb63dd 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 22:45 upstream 91ec20351349 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 20:35 upstream 91ec20351349 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 20:21 upstream 91ec20351349 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 20:18 upstream 91ec20351349 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 20:17 upstream 91ec20351349 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 20:17 upstream 91ec20351349 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 20:17 upstream 91ec20351349 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 20:15 upstream 91ec20351349 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 20:15 upstream 91ec20351349 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 18:59 upstream 91ec20351349 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 18:59 upstream 91ec20351349 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 18:59 upstream 91ec20351349 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 07:37 upstream f4cdf7ca9a1f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 07:33 upstream f4cdf7ca9a1f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 00:38 upstream f4cdf7ca9a1f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 00:38 upstream f4cdf7ca9a1f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/20 00:33 upstream f4cdf7ca9a1f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/19 22:32 upstream f4cdf7ca9a1f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/19 22:31 upstream f4cdf7ca9a1f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/19 22:31 upstream f4cdf7ca9a1f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/19 22:29 upstream f4cdf7ca9a1f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/19 22:29 upstream f4cdf7ca9a1f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/19 22:29 upstream f4cdf7ca9a1f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/19 22:20 upstream f4cdf7ca9a1f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/19 22:19 upstream f4cdf7ca9a1f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/19 22:13 upstream f4cdf7ca9a1f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/19 22:13 upstream f4cdf7ca9a1f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/19 22:13 upstream f4cdf7ca9a1f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/19 22:13 upstream f4cdf7ca9a1f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/19 21:15 upstream f4cdf7ca9a1f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/19 21:15 upstream f4cdf7ca9a1f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/19 21:15 upstream f4cdf7ca9a1f 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in __vb2_queue_cancel
2026/08/19 21:15 upstream f4cdf7ca9a1f 1e72964b .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.