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 87981067 P4D 87981067 PUD 9898d067 PMD 0 Oops: 0002 [#1] PREEMPT SMP KASAN Modules linked in: CPU: 0 PID: 18958 Comm: syz-executor.4 Not tainted 4.14.131 #25 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff88805819a500 task.stack: ffff8880616f8000 RIP: 0010:atomic_inc arch/x86/include/asm/atomic.h:92 [inline] RIP: 0010:kthread_stop+0x4c/0x650 kernel/kthread.c:525 RSP: 0018:ffff8880616ffb88 EFLAGS: 00010216 RAX: 0000000000040000 RBX: 0000000000000000 RCX: ffffc9000ac74000 RDX: 000000000000040d RSI: ffffffff813e150c RDI: 0000000000000286 RBP: ffff8880616ffba8 R08: ffff88805819a500 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffff88809f323cf8 R14: ffff888092e44230 R15: ffff888092e44228 FS: 00007ff50f462700(0000) GS:ffff8880aee00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000020 CR3: 0000000099e59000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: sdr_cap_stop_streaming+0x1fc/0x320 drivers/media/platform/vivid/vivid-sdr-cap.c:313 __vb2_queue_cancel+0xa3/0x890 drivers/media/v4l2-core/videobuf2-core.c:1655 kobject: 'loop5' (ffff8880a4b292e0): kobject_uevent_env vb2_core_streamoff+0x52/0x110 drivers/media/v4l2-core/videobuf2-core.c:1788 kobject: 'loop5' (ffff8880a4b292e0): fill_kobj_path: path = '/devices/virtual/block/loop5' __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 kobject: 'loop5' (ffff8880a4b292e0): kobject_uevent_env 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: 0033:0x459519 RSP: 002b:00007ff50f461c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000459519 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff50f4626d4 R13: 00000000004f85b2 R14: 00000000004d1370 R15: 00000000ffffffff Code: 00 65 8b 1d 47 6c c3 7e 83 fb 3f 0f 87 5e kobject: 'loop5' (ffff8880a4b292e0): fill_kobj_path: path = '/devices/virtual/block/loop5' 04 00 00 e8 89 92 1e 00 89 db 48 0f a3 1d 1f f8 e6 06 0f 82 47 03 00 00 e8 74 92 1e 00 41 ff 44 24 20 49 8d 7c 24 24 48 b8 00 00 00 00 00 fc ff df kauditd_printk_skb: 9 callbacks suppressed audit: type=1800 audit(1561981045.230:136): pid=18971 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="collect_data" cause="failed(directio)" comm="syz-executor.5" name="file0" dev="sda1" ino=16738 res=0 RIP: atomic_inc arch/x86/include/asm/atomic.h:92 [inline] RSP: ffff8880616ffb88 RIP: kthread_stop+0x4c/0x650 kernel/kthread.c:525 RSP: ffff8880616ffb88 CR2: 0000000000000020 kobject: 'loop3' (ffff8880a4a74960): kobject_uevent_env kobject: 'loop3' (ffff8880a4a74960): fill_kobj_path: path = '/devices/virtual/block/loop3' kobject: 'loop1' (ffff8880a49c4660): kobject_uevent_env kobject: 'ppp0' (ffff888061f00f70): kobject_cleanup, parent (null) kobject: 'loop1' (ffff8880a49c4660): fill_kobj_path: path = '/devices/virtual/block/loop1' kobject: 'ppp0' (ffff888061f00f70): calling ktype release kobject: 'ppp0': free name kobject: 'loop2' (ffff8880a4a10f60): kobject_uevent_env kobject: 'loop2' (ffff8880a4a10f60): fill_kobj_path: path = '/devices/virtual/block/loop2' kobject: 'loop2' (ffff8880a4a10f60): kobject_uevent_env kobject: 'loop2' (ffff8880a4a10f60): fill_kobj_path: path = '/devices/virtual/block/loop2' audit: type=1800 audit(1561981045.880:137): pid=18986 uid=0 auid=4294967295 ses=4294967295 subj=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 op="collect_data" cause="failed(directio)" comm="syz-executor.5" name="file0" dev="sda1" ino=16738 res=0 ---[ end trace 4ddcfe2f21db77d6 ]--- kobject: 'loop0' (ffff8880a1f00ea0): kobject_uevent_env kobject: 'loop0' (ffff8880a1f00ea0): fill_kobj_path: path = '/devices/virtual/block/loop0'