INFO: task syz-executor5:14423 blocked for more than 140 seconds. Not tainted 5.0.0-rc1-next-20190110 #9 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor5 D24072 14423 8060 0x00000004 Call Trace: context_switch kernel/sched/core.c:2834 [inline] __schedule+0x897/0x1e60 kernel/sched/core.c:3475 schedule+0xfe/0x350 kernel/sched/core.c:3519 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3577 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0xa3b/0x1670 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 _vb2_fop_release+0x3f/0x2a0 drivers/media/common/videobuf2/videobuf2-v4l2.c:1030 vb2_fop_release+0x75/0xc0 drivers/media/common/videobuf2/videobuf2-v4l2.c:1046 v4l2_release+0x2f2/0x3a0 drivers/media/v4l2-core/v4l2-dev.c:459 __fput+0x3c5/0xb10 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x1f4/0x2b0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x32a/0x3b0 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+0x696/0x800 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x411c91 Code: Bad RIP value. RSP: 002b:00007ffcd7169a40 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000411c91 RDX: 0000000000000000 RSI: 00000000007404a8 RDI: 0000000000000004 RBP: 0000000000000000 R08: 00000000007404a0 R09: 0000000000000000 R10: 00007ffcd7169960 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000001 R14: 0000000000000a9f R15: 0000000000000005 INFO: task syz-executor5:14424 blocked for more than 140 seconds. Not tainted 5.0.0-rc1-next-20190110 #9 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor5 D23688 14424 8060 0x00000004 Call Trace: context_switch kernel/sched/core.c:2834 [inline] __schedule+0x897/0x1e60 kernel/sched/core.c:3475 schedule+0xfe/0x350 kernel/sched/core.c:3519 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3577 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0xa3b/0x1670 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 _vb2_fop_release+0x3f/0x2a0 drivers/media/common/videobuf2/videobuf2-v4l2.c:1030 vb2_fop_release+0x75/0xc0 drivers/media/common/videobuf2/videobuf2-v4l2.c:1046 v4l2_release+0x2f2/0x3a0 drivers/media/v4l2-core/v4l2-dev.c:459 __fput+0x3c5/0xb10 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x1f4/0x2b0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x32a/0x3b0 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+0x696/0x800 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457ec9 Code: Bad RIP value. RSP: 002b:00007fd948db6c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: fffffffffffffff4 RBX: 0000000000000003 RCX: 0000000000457ec9 RDX: 0000000020000040 RSI: 00000000c100565c RDI: 0000000000000003 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd948db76d4 R13: 00000000004c2849 R14: 00000000004d4ee8 R15: 00000000ffffffff INFO: task syz-executor1:14425 blocked for more than 140 seconds. Not tainted 5.0.0-rc1-next-20190110 #9 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor1 D25928 14425 25944 0x00000004 Call Trace: context_switch kernel/sched/core.c:2834 [inline] __schedule+0x897/0x1e60 kernel/sched/core.c:3475 schedule+0xfe/0x350 kernel/sched/core.c:3519 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3577 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0xa3b/0x1670 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 _vb2_fop_release+0x3f/0x2a0 drivers/media/common/videobuf2/videobuf2-v4l2.c:1030 vb2_fop_release+0x75/0xc0 drivers/media/common/videobuf2/videobuf2-v4l2.c:1046 v4l2_release+0x2f2/0x3a0 drivers/media/v4l2-core/v4l2-dev.c:459 __fput+0x3c5/0xb10 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x1f4/0x2b0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x32a/0x3b0 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+0x696/0x800 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x411c91 Code: Bad RIP value. RSP: 002b:00007ffd476e4250 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000007 RCX: 0000000000411c91 RDX: 0000000000000000 RSI: 00000000007405b0 RDI: 0000000000000006 RBP: 0000000000000000 R08: 00000000007405a8 R09: 0000000000000000 R10: 00007ffd476e4170 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000001 R14: 0000000000000346 R15: 0000000000000001 Showing all locks held in the system: 3 locks held by init/1: 1 lock held by khungtaskd/1041: #0: 000000003e86bda1 (rcu_read_lock){....}, at: debug_show_all_locks+0xc6/0x41d kernel/locking/lockdep.c:4408 3 locks held by udevd/3866: 4 locks held by rs:main Q:Reg/7916: 3 locks held by rsyslogd/7918: 3 locks held by cron/7958: 2 locks held by getty/8008: #0: 00000000d8bdb5b4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000099fd5273 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/8009: #0: 00000000f4873364 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000002eda49f3 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/8010: #0: 000000002b33afdd (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000037eb19bc (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/8011: #0: 00000000ed10454d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000dfe99369 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/8012: #0: 00000000a7ece7ba (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000006b2de8c0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/8013: #0: 00000000dee977f5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000007f3666c0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by getty/8014: #0: 000000006617535d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000e6074f64 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x30a/0x1eb0 drivers/tty/n_tty.c:2154 2 locks held by syz-fuzzer/8030: #0: 000000008aa78fb8 (&ei->i_mmap_sem){++++}, at: ext4_filemap_fault+0x7b/0xaf fs/ext4/inode.c:6326 #1: 00000000ece391bb (fs_reclaim){+.+.}, at: fs_reclaim_acquire.part.0+0x0/0x30 include/linux/mm.h:1056 1 lock held by syz-fuzzer/8039: 1 lock held by syz-executor5/14423: #0: 00000000651cce5c (&vcap->lock){+.+.}, at: _vb2_fop_release+0x3f/0x2a0 drivers/media/common/videobuf2/videobuf2-v4l2.c:1030 1 lock held by syz-executor5/14424: #0: 00000000651cce5c (&vcap->lock){+.+.}, at: _vb2_fop_release+0x3f/0x2a0 drivers/media/common/videobuf2/videobuf2-v4l2.c:1030 1 lock held by syz-executor1/14425: #0: 00000000651cce5c (&vcap->lock){+.+.}, at: _vb2_fop_release+0x3f/0x2a0 drivers/media/common/videobuf2/videobuf2-v4l2.c:1030 3 locks held by syz-executor1/14426: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1041 Comm: khungtaskd Not tainted 5.0.0-rc1-next-20190110 #9 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+0x1db/0x2d0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1be/0x236 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:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0xbbb/0x1170 kernel/hung_task.c:287 kthread+0x357/0x430 kernel/kthread.c:247 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: