BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
IP: atomic_inc arch/x86/include/asm/atomic.h:92 [inline]
IP: kthread_stop+0x4c/0x650 kernel/kthread.c:525
PGD 9fbc4067 P4D 9fbc4067 PUD a1d99067 PMD 0 
Oops: 0002 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 7852 Comm: syz-executor.4 Not tainted 4.14.127 #21
kobject: 'nullb0' (ffff8880a3d4d4a0): kobject_uevent_env
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8880a716e240 task.stack: ffff88805e9c8000
RIP: 0010:atomic_inc arch/x86/include/asm/atomic.h:92 [inline]
RIP: 0010:kthread_stop+0x4c/0x650 kernel/kthread.c:525
RSP: 0018:ffff88805e9cfb50 EFLAGS: 00010216
kobject: 'nullb0' (ffff8880a3d4d4a0): fill_kobj_path: path = '/devices/virtual/block/nullb0'
RAX: 0000000000040000 RBX: 0000000000000001 RCX: ffffc9000a27f000
RDX: 0000000000000372 RSI: ffffffff813e152c RDI: 0000000000000286
RBP: ffff88805e9cfb70 R08: ffff8880a716e240 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff888086bc4970 R14: ffff888086bc4968 R15: ffffffff89bb8be0
FS:  00007f0cb1c26700(0000) GS:ffff8880aef00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000020 CR3: 000000008b7b2000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 vivid_stop_generating_vid_cap+0x1b9/0x664 drivers/media/platform/vivid/vivid-kthread-cap.c:934
 vid_cap_stop_streaming+0x7c/0xd0 drivers/media/platform/vivid/vivid-vid-cap.c:273
 __vb2_queue_cancel+0xa3/0x890 drivers/media/v4l2-core/videobuf2-core.c:1655
 vb2_core_streamoff+0x52/0x110 drivers/media/v4l2-core/videobuf2-core.c:1788
 __vb2_cleanup_fileio+0x78/0x150 drivers/media/v4l2-core/videobuf2-core.c:2313
 vb2_core_queue_release+0x1d/0x80 drivers/media/v4l2-core/videobuf2-core.c:2040
 vb2_queue_release drivers/media/v4l2-core/videobuf2-v4l2.c:669 [inline]
 _vb2_fop_release+0x1cf/0x2a0 drivers/media/v4l2-core/videobuf2-v4l2.c:840
 vb2_fop_release+0x75/0xc0 drivers/media/v4l2-core/videobuf2-v4l2.c:854
 vivid_fop_release+0x180/0x3f0 drivers/media/platform/vivid/vivid-core.c:486
 v4l2_release+0xf9/0x190 drivers/media/v4l2-core/v4l2-dev.c:446
 __fput+0x275/0x7a0 fs/file_table.c:210
 ____fput+0x16/0x20 fs/file_table.c:244
 task_work_run+0x114/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1da/0x220 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4bc/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4592c9
RSP: 002b:00007f0cb1c25c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 00000000004592c9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f0cb1c266d4
R13: 00000000004f8052 R14: 00000000004d0e30 R15: 00000000ffffffff
Code: 00 65 8b 1d 27 6c c3 7e 83 fb 3f 0f 87 5e 04 00 00 e8 f9 92 1e 00 89 db 48 0f a3 1d 7f f5 e6 06 0f 82 47 03 00 00 e8 e4 92 1e 00 <f0> 41 ff 44 24 20 49 8d 7c 24 24 48 b8 00 00 00 00 00 fc ff df 
RIP: atomic_inc arch/x86/include/asm/atomic.h:92 [inline] RSP: ffff88805e9cfb50
RIP: kthread_stop+0x4c/0x650 kernel/kthread.c:525 RSP: ffff88805e9cfb50
CR2: 0000000000000020
kobject: 'loop2' (ffff8880a4a417a0): kobject_uevent_env
---[ end trace 4c5eb06a488dd428 ]---
kobject: 'loop2' (ffff8880a4a417a0): fill_kobj_path: path = '/devices/virtual/block/loop2'