INFO: task loop0:10456 blocked for more than 120 seconds.
Not tainted 4.15.0-rc9+ #284
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
loop0 D24976 10456 2 0x80000000
Call Trace:
context_switch kernel/sched/core.c:2799 [inline]
__schedule+0x8eb/0x2060 kernel/sched/core.c:3375
schedule+0xf5/0x430 kernel/sched/core.c:3434
schedule_timeout+0x1a3/0x230 kernel/time/timer.c:1769
io_schedule_timeout+0x26/0x80 kernel/sched/core.c:5030
do_wait_for_common kernel/sched/completion.c:86 [inline]
__wait_for_common kernel/sched/completion.c:107 [inline]
wait_for_common_io kernel/sched/completion.c:124 [inline]
wait_for_completion_io+0x415/0x770 kernel/sched/completion.c:172
submit_bio_wait+0x13f/0x1e0 block/bio.c:947
blkdev_issue_flush+0x226/0x310 block/blk-flush.c:548
blkdev_fsync+0x86/0xb0 fs/block_dev.c:632
vfs_fsync_range+0x110/0x260 fs/sync.c:196
vfs_fsync+0x29/0x30 fs/sync.c:210
lo_req_flush drivers/block/loop.c:444 [inline]
do_req_filebacked drivers/block/loop.c:572 [inline]
loop_handle_cmd drivers/block/loop.c:1724 [inline]
loop_queue_work+0x12a2/0x3900 drivers/block/loop.c:1738
kthread_worker_fn+0x32b/0x980 kernel/kthread.c:642
loop_kthread_worker_fn+0x51/0x60 drivers/block/loop.c:841
kthread+0x33c/0x400 kernel/kthread.c:238
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:541
Showing all locks held in the system:
2 locks held by khungtaskd/759:
#0: (rcu_read_lock){....}, at: [<00000000f6190708>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline]
#0: (rcu_read_lock){....}, at: [<00000000f6190708>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249
#1: (tasklist_lock){.+.+}, at: [<000000006ca9da8f>] debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4465
1 lock held by rsyslogd/3528:
#0: (&f->f_pos_lock){+.+.}, at: [<00000000ba6760eb>] __fdget_pos+0x12b/0x190 fs/file.c:770
2 locks held by getty/3650:
#0: (&tty->ldisc_sem){++++}, at: [<000000004af9c0b5>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<000000003daeae64>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/3651:
#0: (&tty->ldisc_sem){++++}, at: [<000000004af9c0b5>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<000000003daeae64>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/3652:
#0: (&tty->ldisc_sem){++++}, at: [<000000004af9c0b5>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<000000003daeae64>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/3653:
#0: (&tty->ldisc_sem){++++}, at: [<000000004af9c0b5>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<000000003daeae64>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/3654:
#0: (&tty->ldisc_sem){++++}, at: [<000000004af9c0b5>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<000000003daeae64>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/3655:
#0: (&tty->ldisc_sem){++++}, at: [<000000004af9c0b5>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<000000003daeae64>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/3656:
#0: (&tty->ldisc_sem){++++}, at: [<000000004af9c0b5>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<000000003daeae64>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
1 lock held by syz-executor4/17805:
#0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000c31330f7>] lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1355
1 lock held by syz-executor4/17819:
#0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000c31330f7>] lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1355
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 759 Comm: khungtaskd Not tainted 4.15.0-rc9+ #284
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x194/0x257 lib/dump_stack.c:53
nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103
nmi_trigger_cpumask_backtrace+0x122/0x180 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:138 [inline]
check_hung_task kernel/hung_task.c:132 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline]
watchdog+0x90c/0xd60 kernel/hung_task.c:249
kthread+0x33c/0x400 kernel/kthread.c:238
ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:541
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:54