syzbot

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