[syzbot] [media?] INFO: trying to register non-static key in __vb2_queue_cancel

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cc2b5f627e8c Add linux-next specific files for 20260714
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=17fb04b9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2290ccbf984c524f
dashboard link: https://syzkaller.appspot.com/bug?extid=2302c5dc59995fbb8089
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12d598b9580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14500789580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6836f8efb1da/disk-cc2b5f62.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0109d3477cc7/vmlinux-cc2b5f62.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c2e49e350bbf/bzImage-cc2b5f62.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2302c5...@syzkaller.appspotmail.com

em28xx 1-1:0.132: AC97 chip type couldn't be determined
em28xx 1-1:0.132: No AC97 audio processor
usb 1-1: Decoder not found
em28xx 1-1:0.132: failed to create media graph
em28xx 1-1:0.132: V4L2 device video103 deregistered
INFO: trying to register non-static key.
The code is fine but needs lockdep annotation, or maybe
you didn't initialize this object before use?
turning off the locking correctness validator.
CPU: 1 UID: 0 PID: 5649 Comm: kworker/1:3 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
Workqueue: events request_module_async
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
assign_lock_key+0x133/0x150 kernel/locking/lockdep.c:1000
register_lock_class+0xcc/0x2e0 kernel/locking/lockdep.c:1315
__lock_acquire+0xaf/0x2e40 kernel/locking/lockdep.c:5128
lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5906
rt_spin_lock+0x83/0x400 kernel/locking/spinlock_rt.c:56
spin_lock include/linux/spinlock_rt.h:45 [inline]
__wake_up_common_lock+0x2f/0x1f0 kernel/sched/wait.c:124
__vb2_queue_cancel+0x2de/0xdc0 drivers/media/common/videobuf2/videobuf2-core.c:2244
vb2_core_queue_release+0x2f/0x150 drivers/media/common/videobuf2/videobuf2-core.c:2677
vb2_queue_release drivers/media/common/videobuf2/videobuf2-v4l2.c:956 [inline]
vb2_video_unregister_device+0x15b/0x200 drivers/media/common/videobuf2/videobuf2-v4l2.c:1292
em28xx_v4l2_init+0x1c60/0x3140 drivers/media/usb/em28xx/em28xx-video.c:3097
em28xx_init_extension+0x120/0x1d0 drivers/media/usb/em28xx/em28xx-core.c:1248
process_one_work+0xaaf/0x1480 kernel/workqueue.c:3379
process_scheduled_works kernel/workqueue.c:3462 [inline]
worker_thread+0xb05/0x10d0 kernel/workqueue.c:3543
kthread+0x388/0x470 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>
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 UID: 0 PID: 5649 Comm: kworker/1:3 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
Workqueue: events request_module_async
RIP: 0010:__wake_up_common kernel/sched/wait.c:104 [inline]
RIP: 0010:__wake_up_common_lock+0xd6/0x1f0 kernel/sched/wait.c:125
Code: 0f 84 d4 00 00 00 44 8b 7c 24 04 eb 13 48 ba 00 00 00 00 00 fc ff df 4c 39 ed 0f 84 ba 00 00 00 49 89 ee 48 89 e8 48 c1 e8 03 <80> 3c 10 00 74 12 4c 89 f7 e8 1c ce 93 00 48 ba 00 00 00 00 00 fc
RSP: 0018:ffffc9000595f908 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: ffffffff8bcbd060 RDI: 00000000ffffffff
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1fa1890 R12: ffff88803e181b14
R13: ffff88803e181c28 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125af2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005625301fb660 CR3: 000000003774e000 CR4: 00000000003526f0
Call Trace:
<TASK>
__vb2_queue_cancel+0x2de/0xdc0 drivers/media/common/videobuf2/videobuf2-core.c:2244
vb2_core_queue_release+0x2f/0x150 drivers/media/common/videobuf2/videobuf2-core.c:2677
vb2_queue_release drivers/media/common/videobuf2/videobuf2-v4l2.c:956 [inline]
vb2_video_unregister_device+0x15b/0x200 drivers/media/common/videobuf2/videobuf2-v4l2.c:1292
em28xx_v4l2_init+0x1c60/0x3140 drivers/media/usb/em28xx/em28xx-video.c:3097
em28xx_init_extension+0x120/0x1d0 drivers/media/usb/em28xx/em28xx-core.c:1248
process_one_work+0xaaf/0x1480 kernel/workqueue.c:3379
process_scheduled_works kernel/workqueue.c:3462 [inline]
worker_thread+0xb05/0x10d0 kernel/workqueue.c:3543
kthread+0x388/0x470 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:__wake_up_common kernel/sched/wait.c:104 [inline]
RIP: 0010:__wake_up_common_lock+0xd6/0x1f0 kernel/sched/wait.c:125
Code: 0f 84 d4 00 00 00 44 8b 7c 24 04 eb 13 48 ba 00 00 00 00 00 fc ff df 4c 39 ed 0f 84 ba 00 00 00 49 89 ee 48 89 e8 48 c1 e8 03 <80> 3c 10 00 74 12 4c 89 f7 e8 1c ce 93 00 48 ba 00 00 00 00 00 fc
RSP: 0018:ffffc9000595f908 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: ffffffff8bcbd060 RDI: 00000000ffffffff
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1fa1890 R12: ffff88803e181b14
R13: ffff88803e181c28 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125af2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005625301fb660 CR3: 000000003774e000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
0: 0f 84 d4 00 00 00 je 0xda
6: 44 8b 7c 24 04 mov 0x4(%rsp),%r15d
b: eb 13 jmp 0x20
d: 48 ba 00 00 00 00 00 movabs $0xdffffc0000000000,%rdx
14: fc ff df
17: 4c 39 ed cmp %r13,%rbp
1a: 0f 84 ba 00 00 00 je 0xda
20: 49 89 ee mov %rbp,%r14
23: 48 89 e8 mov %rbp,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 80 3c 10 00 cmpb $0x0,(%rax,%rdx,1) <-- trapping instruction
2e: 74 12 je 0x42
30: 4c 89 f7 mov %r14,%rdi
33: e8 1c ce 93 00 call 0x93ce54
38: 48 rex.W
39: ba 00 00 00 00 mov $0x0,%edx
3e: 00 fc add %bh,%ah


---
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[Gautam Bhadoria]

#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git cc2b5f627e8ccbae1188ef2d8be3e451d7f933a5

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
lost connection to test machine



Tested on:

commit: cc2b5f62 Add linux-next specific files for 20260714
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=117a58b9580000

kernel config: https://syzkaller.appspot.com/x/.config?x=2290ccbf984c524f
dashboard link: https://syzkaller.appspot.com/bug?extid=2302c5dc59995fbb8089
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

patch: https://syzkaller.appspot.com/x/patch.diff?x=167ff346580000

[Gautam Bhadoria]

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git

cc2b5f627e8ccbae1188ef2d8be3e451d7f933a5  

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
lost connection to test machine



Tested on:

commit: cc2b5f62 Add linux-next specific files for 20260714

git tree: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=11d20b46580000

kernel config: https://syzkaller.appspot.com/x/.config?x=2290ccbf984c524f
dashboard link: https://syzkaller.appspot.com/bug?extid=2302c5dc59995fbb8089
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

patch: https://syzkaller.appspot.com/x/patch.diff?x=17d658b9580000