INFO: task hung in vivid_stop_generating_vid_cap

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syzbot

unread,
Oct 29, 2018, 5:40:03 AM10/29/18
to hver...@xs4all.nl, linux-...@vger.kernel.org, linux...@vger.kernel.org, mch...@kernel.org, syzkall...@googlegroups.com
Hello,

syzbot found the following crash on:

HEAD commit: 8c60c36d0b8c Add linux-next specific files for 20181019
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1608ccf5400000
kernel config: https://syzkaller.appspot.com/x/.config?x=ddc97ab84fb1ff2a
dashboard link: https://syzkaller.appspot.com/bug?extid=06283a66a648cd073885
compiler: gcc (GCC) 8.0.1 20180413 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+06283a...@syzkaller.appspotmail.com

VMExit: intr_info=00000000 errcode=00000000 ilen=00000003
reason=80000021 qualification=0000000000000003
IDTVectoring: info=00000000 errcode=00000000
TSC Offset = 0xfffffe6382838c64
EPT pointer = 0x00000001c4f5101e
INFO: task syz-executor4:791 blocked for more than 140 seconds.
Not tainted 4.19.0-rc8-next-20181019+ #99
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor4 D23272 791 5784 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2831 [inline]
__schedule+0x8cf/0x21d0 kernel/sched/core.c:3480
schedule+0xfe/0x460 kernel/sched/core.c:3524
schedule_timeout+0x1cc/0x260 kernel/time/timer.c:1780
do_wait_for_common kernel/sched/completion.c:83 [inline]
__wait_for_common kernel/sched/completion.c:104 [inline]
wait_for_common kernel/sched/completion.c:115 [inline]
wait_for_completion+0x427/0x8a0 kernel/sched/completion.c:136
kthread_stop+0x1a4/0x8f0 kernel/kthread.c:550
vivid_stop_generating_vid_cap+0x2bc/0x93b
drivers/media/platform/vivid/vivid-kthread-cap.c:919
vid_cap_stop_streaming+0x8d/0xe0
drivers/media/platform/vivid/vivid-vid-cap.c:259
__vb2_queue_cancel+0x171/0xca0
drivers/media/common/videobuf2/videobuf2-core.c:1668
vb2_core_streamoff+0x60/0x140
drivers/media/common/videobuf2/videobuf2-core.c:1804
__vb2_cleanup_fileio+0x73/0x160
drivers/media/common/videobuf2/videobuf2-core.c:2325
vb2_core_queue_release+0x1e/0x80
drivers/media/common/videobuf2/videobuf2-core.c:2052
vb2_queue_release drivers/media/common/videobuf2/videobuf2-v4l2.c:672
[inline]
_vb2_fop_release+0x1d2/0x2b0
drivers/media/common/videobuf2/videobuf2-v4l2.c:843
vb2_fop_release+0x77/0xc0
drivers/media/common/videobuf2/videobuf2-v4l2.c:857
vivid_fop_release+0x18e/0x440 drivers/media/platform/vivid/vivid-core.c:474
v4l2_release+0xfb/0x1a0 drivers/media/v4l2-core/v4l2-dev.c:448
__fput+0x3bc/0xa70 fs/file_table.c:279
____fput+0x15/0x20 fs/file_table.c:312
task_work_run+0x1e8/0x2a0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166
prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x411021
Code: 4c 89 f6 48 89 c7 48 89 ca 48 89 4c 24 10 4c 89 54 24 08 e8 b1 a3 ff
ff 48 8b 4c 24 10 41 c6 04 0f 00 4c 8b 7c 24 28 4c 8b 54 <24> 08 45 0f b6
37 e9 db fc ff ff 0f 1f 40 00 41 80 f8 29 74 7f ba
RSP: 002b:00007ffebf8f0810 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000411021
RDX: 0000001b2ca20000 RSI: 0000000000730430 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000030c04255 R09: 0000000030c04259
R10: 00007ffebf8f0740 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000001 R14: 0000000000000447 R15: 0000000000000004

Showing all locks held in the system:
1 lock held by khungtaskd/1008:
#0: 00000000b994d395 (rcu_read_lock){....}, at:
debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4379
1 lock held by rsyslogd/5554:
#0: 0000000064483821 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200
fs/file.c:766
2 locks held by getty/5644:
#0: 0000000088b7a22a (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 000000003463365c (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154
2 locks held by getty/5645:
#0: 00000000b07a05bf (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 00000000accbc122 (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154
2 locks held by getty/5646:
#0: 000000003b71eb89 (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 00000000e3b18d3f (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154
2 locks held by getty/5647:
#0: 00000000c8f2c425 (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 00000000646fd3b6 (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154
2 locks held by getty/5648:
#0: 000000004a4ae0cc (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 00000000d9aa1576 (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154
2 locks held by getty/5649:
#0: 000000001d616490 (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 00000000865e3bcf (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154
2 locks held by getty/5650:
#0: 00000000c8214d1d (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 00000000782baf35 (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 1008 Comm: khungtaskd Not tainted 4.19.0-rc8-next-20181019+ #99
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x244/0x39d lib/dump_stack.c:113
nmi_cpu_backtrace.cold.2+0x5c/0xa1 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x1e8/0x22a lib/nmi_backtrace.c:62
arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
trigger_all_cpu_backtrace include/linux/nmi.h:144 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:204 [inline]
watchdog+0xb39/0x1050 kernel/hung_task.c:265
kthread+0x35a/0x440 kernel/kthread.c:246
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0x6/0x10
arch/x86/include/asm/irqflags.h:57


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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syzbot.

syzbot

unread,
Oct 29, 2018, 12:22:04 PM10/29/18
to hver...@xs4all.nl, linux-...@vger.kernel.org, linux...@vger.kernel.org, mch...@kernel.org, syzkall...@googlegroups.com
syzbot has found a reproducer for the following crash on:

HEAD commit: 9f51ae62c84a Merge git://git.kernel.org/pub/scm/linux/kern..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14bfad7b400000
kernel config: https://syzkaller.appspot.com/x/.config?x=62118286bb772a24
dashboard link: https://syzkaller.appspot.com/bug?extid=06283a66a648cd073885
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15701a33400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=154c8e4d400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+06283a...@syzkaller.appspotmail.com

INFO: task syz-executor686:5724 blocked for more than 140 seconds.
Not tainted 4.19.0+ #309
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor686 D24208 5724 5716 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2831 [inline]
__schedule+0x8cf/0x21d0 kernel/sched/core.c:3480
schedule+0xfe/0x460 kernel/sched/core.c:3524
schedule_timeout+0x1cc/0x260 kernel/time/timer.c:1780
do_wait_for_common kernel/sched/completion.c:83 [inline]
__wait_for_common kernel/sched/completion.c:104 [inline]
wait_for_common kernel/sched/completion.c:115 [inline]
wait_for_completion+0x427/0x8a0 kernel/sched/completion.c:136
kthread_stop+0x1a9/0x900 kernel/kthread.c:550
vivid_stop_generating_vid_cap+0x2bc/0x93b
drivers/media/platform/vivid/vivid-kthread-cap.c:919
vid_cap_stop_streaming+0x8d/0xe0
drivers/media/platform/vivid/vivid-vid-cap.c:256
__vb2_queue_cancel+0x171/0xca0
drivers/media/common/videobuf2/videobuf2-core.c:1659
vb2_core_streamoff+0x60/0x140
drivers/media/common/videobuf2/videobuf2-core.c:1795
__vb2_cleanup_fileio+0x73/0x160
drivers/media/common/videobuf2/videobuf2-core.c:2316
vb2_core_queue_release+0x1e/0x80
drivers/media/common/videobuf2/videobuf2-core.c:2043
vb2_queue_release drivers/media/common/videobuf2/videobuf2-v4l2.c:672
[inline]
_vb2_fop_release+0x1d2/0x2b0
drivers/media/common/videobuf2/videobuf2-v4l2.c:843
vb2_fop_release+0x77/0xc0
drivers/media/common/videobuf2/videobuf2-v4l2.c:857
vivid_fop_release+0x18e/0x440 drivers/media/platform/vivid/vivid-core.c:474
v4l2_release+0xfb/0x1a0 drivers/media/v4l2-core/v4l2-dev.c:448
__fput+0x385/0xa30 fs/file_table.c:278
____fput+0x15/0x20 fs/file_table.c:309
task_work_run+0x1e8/0x2a0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166
prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x400f00
Code: 00 00 00 00 00 00 00 00 00 00 d6 01 00 00 12 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 03 00 00 12 00 00 00 <00> 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 b8 02 00 00 12 00
RSP: 002b:00007ffc53169f28 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000400f00
RDX: 00000000000000d6 RSI: 0000000020000140 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00000000024b1880 R09: 00000000004002e0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401e10
R13: 0000000000401ea0 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor686:5730 blocked for more than 140 seconds.
Not tainted 4.19.0+ #309
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor686 D24208 5730 5721 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2831 [inline]
__schedule+0x8cf/0x21d0 kernel/sched/core.c:3480
schedule+0xfe/0x460 kernel/sched/core.c:3524
schedule_timeout+0x1cc/0x260 kernel/time/timer.c:1780
do_wait_for_common kernel/sched/completion.c:83 [inline]
__wait_for_common kernel/sched/completion.c:104 [inline]
wait_for_common kernel/sched/completion.c:115 [inline]
wait_for_completion+0x427/0x8a0 kernel/sched/completion.c:136
kthread_stop+0x1a9/0x900 kernel/kthread.c:550
vivid_stop_generating_vid_cap+0x2bc/0x93b
drivers/media/platform/vivid/vivid-kthread-cap.c:919
vid_cap_stop_streaming+0x8d/0xe0
drivers/media/platform/vivid/vivid-vid-cap.c:256
__vb2_queue_cancel+0x171/0xca0
drivers/media/common/videobuf2/videobuf2-core.c:1659
vb2_core_streamoff+0x60/0x140
drivers/media/common/videobuf2/videobuf2-core.c:1795
__vb2_cleanup_fileio+0x73/0x160
drivers/media/common/videobuf2/videobuf2-core.c:2316
vb2_core_queue_release+0x1e/0x80
drivers/media/common/videobuf2/videobuf2-core.c:2043
vb2_queue_release drivers/media/common/videobuf2/videobuf2-v4l2.c:672
[inline]
_vb2_fop_release+0x1d2/0x2b0
drivers/media/common/videobuf2/videobuf2-v4l2.c:843
vb2_fop_release+0x77/0xc0
drivers/media/common/videobuf2/videobuf2-v4l2.c:857
vivid_fop_release+0x18e/0x440 drivers/media/platform/vivid/vivid-core.c:474
v4l2_release+0xfb/0x1a0 drivers/media/v4l2-core/v4l2-dev.c:448
__fput+0x385/0xa30 fs/file_table.c:278
____fput+0x15/0x20 fs/file_table.c:309
task_work_run+0x1e8/0x2a0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166
prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x400f00
Code: 00 00 00 00 00 00 00 00 00 00 d6 01 00 00 12 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 03 00 00 12 00 00 00 <00> 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 b8 02 00 00 12 00
RSP: 002b:00007ffc53169f28 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000400f00
RDX: 00000000000000d6 RSI: 0000000020000140 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00000000024b1880 R09: 00000000004002e0
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000003fbb5
R13: 0000000000401ea0 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor686:5734 blocked for more than 140 seconds.
Not tainted 4.19.0+ #309
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor686 D21848 5734 5720 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2831 [inline]
__schedule+0x8cf/0x21d0 kernel/sched/core.c:3480
schedule+0xfe/0x460 kernel/sched/core.c:3524
schedule_timeout+0x1cc/0x260 kernel/time/timer.c:1780
do_wait_for_common kernel/sched/completion.c:83 [inline]
__wait_for_common kernel/sched/completion.c:104 [inline]
wait_for_common kernel/sched/completion.c:115 [inline]
wait_for_completion+0x427/0x8a0 kernel/sched/completion.c:136
kthread_stop+0x1a9/0x900 kernel/kthread.c:550
vivid_stop_generating_vid_cap+0x2bc/0x93b
drivers/media/platform/vivid/vivid-kthread-cap.c:919
vid_cap_stop_streaming+0x8d/0xe0
drivers/media/platform/vivid/vivid-vid-cap.c:256
__vb2_queue_cancel+0x171/0xca0
drivers/media/common/videobuf2/videobuf2-core.c:1659
vb2_core_streamoff+0x60/0x140
drivers/media/common/videobuf2/videobuf2-core.c:1795
__vb2_cleanup_fileio+0x73/0x160
drivers/media/common/videobuf2/videobuf2-core.c:2316
vb2_core_queue_release+0x1e/0x80
drivers/media/common/videobuf2/videobuf2-core.c:2043
vb2_queue_release drivers/media/common/videobuf2/videobuf2-v4l2.c:672
[inline]
_vb2_fop_release+0x1d2/0x2b0
drivers/media/common/videobuf2/videobuf2-v4l2.c:843
vb2_fop_release+0x77/0xc0
drivers/media/common/videobuf2/videobuf2-v4l2.c:857
vivid_fop_release+0x18e/0x440 drivers/media/platform/vivid/vivid-core.c:474
v4l2_release+0xfb/0x1a0 drivers/media/v4l2-core/v4l2-dev.c:448
__fput+0x385/0xa30 fs/file_table.c:278
____fput+0x15/0x20 fs/file_table.c:309
task_work_run+0x1e8/0x2a0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166
prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x400f00
Code: 00 00 00 00 00 00 a8 01 00 00 00 00 00 00 36 01 00 00 b5 00 00 00 01
02 00 00 00 00 00 00 00 00 00 00 6a 01 00 00 00 00 00 00 <00> 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
RSP: 002b:00007ffc53169f28 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000400f00
RDX: 00000000000000d6 RSI: 0000000020000140 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00000000024b1880 R09: 00000000004002e0
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000003fbc6
R13: 0000000000401ea0 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor686:5881 blocked for more than 140 seconds.
Not tainted 4.19.0+ #309
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor686 D24208 5881 5715 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2831 [inline]
__schedule+0x8cf/0x21d0 kernel/sched/core.c:3480
schedule+0xfe/0x460 kernel/sched/core.c:3524
schedule_timeout+0x1cc/0x260 kernel/time/timer.c:1780
do_wait_for_common kernel/sched/completion.c:83 [inline]
__wait_for_common kernel/sched/completion.c:104 [inline]
wait_for_common kernel/sched/completion.c:115 [inline]
wait_for_completion+0x427/0x8a0 kernel/sched/completion.c:136
kthread_stop+0x1a9/0x900 kernel/kthread.c:550
vivid_stop_generating_vid_cap+0x2bc/0x93b
drivers/media/platform/vivid/vivid-kthread-cap.c:919
vid_cap_stop_streaming+0x8d/0xe0
drivers/media/platform/vivid/vivid-vid-cap.c:256
__vb2_queue_cancel+0x171/0xca0
drivers/media/common/videobuf2/videobuf2-core.c:1659
vb2_core_streamoff+0x60/0x140
drivers/media/common/videobuf2/videobuf2-core.c:1795
__vb2_cleanup_fileio+0x73/0x160
drivers/media/common/videobuf2/videobuf2-core.c:2316
vb2_core_queue_release+0x1e/0x80
drivers/media/common/videobuf2/videobuf2-core.c:2043
vb2_queue_release drivers/media/common/videobuf2/videobuf2-v4l2.c:672
[inline]
_vb2_fop_release+0x1d2/0x2b0
drivers/media/common/videobuf2/videobuf2-v4l2.c:843
vb2_fop_release+0x77/0xc0
drivers/media/common/videobuf2/videobuf2-v4l2.c:857
vivid_fop_release+0x18e/0x440 drivers/media/platform/vivid/vivid-core.c:474
v4l2_release+0xfb/0x1a0 drivers/media/v4l2-core/v4l2-dev.c:448
__fput+0x385/0xa30 fs/file_table.c:278
____fput+0x15/0x20 fs/file_table.c:309
task_work_run+0x1e8/0x2a0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166
prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x400f00
Code: 00 00 00 00 00 00 a8 01 00 00 00 00 00 00 36 01 00 00 b5 00 00 00 01
02 00 00 00 00 00 00 00 00 00 00 6a 01 00 00 00 00 00 00 <00> 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
RSP: 002b:00007ffc53169f28 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000400f00
RDX: 00000000000000d6 RSI: 0000000020000140 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00000000024b1880 R09: 00000000004002e0
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000003fc9c
R13: 0000000000401ea0 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor686:5883 blocked for more than 140 seconds.
Not tainted 4.19.0+ #309
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor686 D24208 5883 5718 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2831 [inline]
__schedule+0x8cf/0x21d0 kernel/sched/core.c:3480
schedule+0xfe/0x460 kernel/sched/core.c:3524
schedule_timeout+0x1cc/0x260 kernel/time/timer.c:1780
do_wait_for_common kernel/sched/completion.c:83 [inline]
__wait_for_common kernel/sched/completion.c:104 [inline]
wait_for_common kernel/sched/completion.c:115 [inline]
wait_for_completion+0x427/0x8a0 kernel/sched/completion.c:136
kthread_stop+0x1a9/0x900 kernel/kthread.c:550
vivid_stop_generating_vid_cap+0x2bc/0x93b
drivers/media/platform/vivid/vivid-kthread-cap.c:919
vid_cap_stop_streaming+0x8d/0xe0
drivers/media/platform/vivid/vivid-vid-cap.c:256
__vb2_queue_cancel+0x171/0xca0
drivers/media/common/videobuf2/videobuf2-core.c:1659
vb2_core_streamoff+0x60/0x140
drivers/media/common/videobuf2/videobuf2-core.c:1795
__vb2_cleanup_fileio+0x73/0x160
drivers/media/common/videobuf2/videobuf2-core.c:2316
vb2_core_queue_release+0x1e/0x80
drivers/media/common/videobuf2/videobuf2-core.c:2043
vb2_queue_release drivers/media/common/videobuf2/videobuf2-v4l2.c:672
[inline]
_vb2_fop_release+0x1d2/0x2b0
drivers/media/common/videobuf2/videobuf2-v4l2.c:843
vb2_fop_release+0x77/0xc0
drivers/media/common/videobuf2/videobuf2-v4l2.c:857
vivid_fop_release+0x18e/0x440 drivers/media/platform/vivid/vivid-core.c:474
v4l2_release+0xfb/0x1a0 drivers/media/v4l2-core/v4l2-dev.c:448
__fput+0x385/0xa30 fs/file_table.c:278
____fput+0x15/0x20 fs/file_table.c:309
task_work_run+0x1e8/0x2a0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:188 [inline]
exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166
prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x400f00
Code: 00 00 00 00 00 00 a8 01 00 00 00 00 00 00 36 01 00 00 b5 00 00 00 01
02 00 00 00 00 00 00 00 00 00 00 6a 01 00 00 00 00 00 00 <00> 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
RSP: 002b:00007ffc53169f28 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000400f00
RDX: 00000000000000d6 RSI: 0000000020000140 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00000000024b1880 R09: 00000000004002e0
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000003fca0
R13: 0000000000401ea0 R14: 0000000000000000 R15: 0000000000000000

Showing all locks held in the system:
1 lock held by khungtaskd/1008:
#0: 00000000313d48c2 (rcu_read_lock){....}, at:
debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4379
2 locks held by rsyslogd/5598:
#0: 00000000b3518de3 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200
fs/file.c:766
#1: 0000000038ba078b (logbuf_lock){-.-.}, at:
is_bpf_text_address+0x0/0x170 kernel/bpf/core.c:533
2 locks held by getty/5688:
#0: 0000000076b566f1 (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 00000000d605404c (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5689:
#0: 0000000001bbb883 (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 00000000bd2d67d2 (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5690:
#0: 000000006d0f3ae6 (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 0000000043ffd330 (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5691:
#0: 000000007bbc59b2 (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 000000002498a126 (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5692:
#0: 000000007b579bf2 (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 000000002e537c6f (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5693:
#0: 0000000034f4df10 (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 00000000d5e3a383 (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/5694:
#0: 00000000b9babf44 (&tty->ldisc_sem){++++}, at:
ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353
#1: 0000000080bdfa70 (&ldata->atomic_read_lock){+.+.}, at:
n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 1008 Comm: khungtaskd Not tainted 4.19.0+ #309
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x244/0x39d lib/dump_stack.c:113
nmi_cpu_backtrace.cold.1+0x5c/0xa1 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x1b3/0x1ed lib/nmi_backtrace.c:62
arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
trigger_all_cpu_backtrace include/linux/nmi.h:144 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:204 [inline]
watchdog+0xb3e/0x1050 kernel/hung_task.c:265
kthread+0x35a/0x440 kernel/kthread.c:246
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:350
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0x6/0x10
arch/x86/include/asm/irqflags.h:57

syzbot

unread,
Mar 22, 2019, 3:08:01 AM3/22/19
to an...@greyhouse.net, da...@davemloft.net, hver...@xs4all.nl, j.vos...@gmail.com, linux-...@vger.kernel.org, linux...@vger.kernel.org, mah...@google.com, mch...@kernel.org, net...@vger.kernel.org, syzkall...@googlegroups.com, vfa...@gmail.com
syzbot has bisected this bug to:

commit 4493b81bea24269df898339dee638d7c5cb2b2df
Author: Mahesh Bandewar <mah...@google.com>
Date: Wed Mar 8 18:55:54 2017 +0000

bonding: initialize work-queues during creation of bond

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=176d1617200000
start commit: 4493b81b bonding: initialize work-queues during creation o..
git tree: upstream
final crash: https://syzkaller.appspot.com/x/report.txt?x=14ed1617200000
console output: https://syzkaller.appspot.com/x/log.txt?x=10ed1617200000
kernel config: https://syzkaller.appspot.com/x/.config?x=62118286bb772a24
dashboard link: https://syzkaller.appspot.com/bug?extid=06283a66a648cd073885
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15701a33400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=154c8e4d400000

Reported-by: syzbot+06283a...@syzkaller.appspotmail.com
Fixes: 4493b81bea24 ("bonding: initialize work-queues during creation of
bond")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

Dmitry Vyukov

unread,
Mar 22, 2019, 4:01:01 AM3/22/19
to syzbot, linu...@vger.kernel.org, an...@greyhouse.net, David Miller, Hans Verkuil, j.vos...@gmail.com, LKML, linux...@vger.kernel.org, Mahesh Bandewar, mch...@kernel.org, netdev, syzkaller-bugs, vfa...@gmail.com
On Fri, Mar 22, 2019 at 8:08 AM syzbot
<syzbot+06283a...@syzkaller.appspotmail.com> wrote:
>
> syzbot has bisected this bug to:
>
> commit 4493b81bea24269df898339dee638d7c5cb2b2df
> Author: Mahesh Bandewar <mah...@google.com>
> Date: Wed Mar 8 18:55:54 2017 +0000
>
> bonding: initialize work-queues during creation of bond

+linux-can

I think I will disable CONFIG_CAN before v4.12. It causes too many
false results for v4.12..v4.11 range. It always leads to a wrong
decision for first 3 steps, then no chances of correct bisection
anymore.

Dmitry Vyukov

unread,
Mar 22, 2019, 4:06:53 AM3/22/19
to syzbot, linu...@vger.kernel.org, an...@greyhouse.net, David Miller, Hans Verkuil, j.vos...@gmail.com, LKML, linux...@vger.kernel.org, Mahesh Bandewar, mch...@kernel.org, netdev, syzkaller-bugs, vfa...@gmail.com
On Fri, Mar 22, 2019 at 9:00 AM Dmitry Vyukov <dvy...@google.com> wrote:
>
> On Fri, Mar 22, 2019 at 8:08 AM syzbot
> <syzbot+06283a...@syzkaller.appspotmail.com> wrote:
> >
> > syzbot has bisected this bug to:
> >
> > commit 4493b81bea24269df898339dee638d7c5cb2b2df
> > Author: Mahesh Bandewar <mah...@google.com>
> > Date: Wed Mar 8 18:55:54 2017 +0000
> >
> > bonding: initialize work-queues during creation of bond
>
> +linux-can
>
> I think I will disable CONFIG_CAN before v4.12. It causes too many
> false results for v4.12..v4.11 range. It always leads to a wrong
> decision for first 3 steps, then no chances of correct bisection
> anymore.

The same seems to show up for v4.12..v4.13:
all runs: crashed: INFO: trying to register non-static key in can_notifier
https://syzkaller.appspot.com/text?tag=Log&x=1555b12b200000

This was fixed by 74b7b490886852582d986a33443c2ffa50970169 right?

syzbot

unread,
Mar 22, 2019, 6:45:01 PM3/22/19
to an...@greyhouse.net, da...@davemloft.net, dvy...@google.com, hans.v...@cisco.com, helen...@collabora.com, hver...@xs4all.nl, j.vos...@gmail.com, linu...@vger.kernel.org, linux-...@vger.kernel.org, linux...@vger.kernel.org, mah...@google.com, mch...@kernel.org, mch...@s-opensource.com, net...@vger.kernel.org, syzkall...@googlegroups.com, vfa...@gmail.com
syzbot has bisected this bug to:

commit f2fe89061d79706eca5c47e4efdc09bbc171e74a
Author: Helen Koike <helen...@collabora.com>
Date: Fri Apr 7 17:55:19 2017 +0000

[media] vimc: Virtual Media Controller core, capture and sensor

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=12ea247d200000
start commit: 9f51ae62 Merge git://git.kernel.org/pub/scm/linux/kernel/g..
git tree: upstream
final crash: https://syzkaller.appspot.com/x/report.txt?x=11ea247d200000
console output: https://syzkaller.appspot.com/x/log.txt?x=16ea247d200000
kernel config: https://syzkaller.appspot.com/x/.config?x=62118286bb772a24
dashboard link: https://syzkaller.appspot.com/bug?extid=06283a66a648cd073885
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15701a33400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=154c8e4d400000

Reported-by: syzbot+06283a...@syzkaller.appspotmail.com
Fixes: f2fe89061d79 ("[media] vimc: Virtual Media Controller core, capture
and sensor")

syzbot

unread,
Nov 7, 2019, 8:42:07 AM11/7/19
to an...@greyhouse.net, da...@davemloft.net, dvy...@google.com, hans.v...@cisco.com, helen...@collabora.com, hverkui...@xs4all.nl, hver...@xs4all.nl, j.vos...@gmail.com, linu...@vger.kernel.org, linux-...@vger.kernel.org, linux...@vger.kernel.org, mah...@google.com, mchehab...@kernel.org, mch...@kernel.org, mch...@s-opensource.com, net...@vger.kernel.org, syzkall...@googlegroups.com, tf...@chromium.org, vfa...@gmail.com
syzbot suspects this bug was fixed by commit:

commit d65842f7126aa1a87fb44b7c9980c12630ed4f33
Author: Hans Verkuil <hver...@xs4all.nl>
Date: Mon Nov 19 11:09:00 2018 +0000

media: vb2: add waiting_in_dqbuf flag

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1417a04a600000
start commit: 9f51ae62 Merge git://git.kernel.org/pub/scm/linux/kernel/g..
git tree: upstream
kernel config: https://syzkaller.appspot.com/x/.config?x=62118286bb772a24
dashboard link: https://syzkaller.appspot.com/bug?extid=06283a66a648cd073885
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15701a33400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=154c8e4d400000

If the result looks correct, please mark the bug fixed by replying with:

#syz fix: media: vb2: add waiting_in_dqbuf flag

Marc Kleine-Budde

unread,
Nov 7, 2019, 1:51:34 PM11/7/19
to Dmitry Vyukov, syzbot, linu...@vger.kernel.org, an...@greyhouse.net, David Miller, Hans Verkuil, j.vos...@gmail.com, LKML, linux...@vger.kernel.org, Mahesh Bandewar, mch...@kernel.org, netdev, syzkaller-bugs, vfa...@gmail.com
On 3/22/19 9:06 AM, Dmitry Vyukov wrote:
> On Fri, Mar 22, 2019 at 9:00 AM Dmitry Vyukov <dvy...@google.com> wrote:
>>
>> On Fri, Mar 22, 2019 at 8:08 AM syzbot
>> <syzbot+06283a...@syzkaller.appspotmail.com> wrote:
>>>
>>> syzbot has bisected this bug to:
>>>
>>> commit 4493b81bea24269df898339dee638d7c5cb2b2df
>>> Author: Mahesh Bandewar <mah...@google.com>
>>> Date: Wed Mar 8 18:55:54 2017 +0000
>>>
>>> bonding: initialize work-queues during creation of bond
>>
>> +linux-can
>>
>> I think I will disable CONFIG_CAN before v4.12. It causes too many
>> false results for v4.12..v4.11 range. It always leads to a wrong
>> decision for first 3 steps, then no chances of correct bisection
>> anymore.
>
> The same seems to show up for v4.12..v4.13:
> all runs: crashed: INFO: trying to register non-static key in can_notifier
> https://syzkaller.appspot.com/text?tag=Log&x=1555b12b200000
>
> This was fixed by 74b7b490886852582d986a33443c2ffa50970169 right?

ACK

Marc

--
Pengutronix e.K. | Marc Kleine-Budde |
Embedded Linux | https://www.pengutronix.de |
Vertretung West/Dortmund | Phone: +49-231-2826-924 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |

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Hans Verkuil

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Nov 11, 2019, 9:01:07 AM11/11/19
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