INFO: task syz-executor0:7167 blocked for more than 120 seconds. Not tainted 4.9.69-g3f1d77c #108 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D29584 7167 3531 0x00000004 ffff8801d0714800 ffff8801d03e4000 ffff8801c817a4c0 ffff8801d1393000 ffff8801db221418 ffff8801c38f7b10 ffffffff8389932b ffffffff81239480 ffff8801c38f7bb8 00ffffff81cfbd9a ffff8801db221ce8 ffff8801db221d10 Call Trace: [] schedule+0x7f/0x1b0 kernel/sched/core.c:3550 [] schedule_timeout+0x643/0x1220 kernel/time/timer.c:1770 [] io_schedule_timeout+0x1be/0x390 kernel/sched/core.c:5172 [] do_wait_for_common kernel/sched/completion.c:75 [inline] [] __wait_for_common kernel/sched/completion.c:93 [inline] [] wait_for_common_io kernel/sched/completion.c:107 [inline] [] wait_for_completion_io+0x20e/0x2e0 kernel/sched/completion.c:155 [] submit_bio_wait+0x11b/0x180 block/bio.c:885 [] blkdev_issue_flush+0x157/0x220 block/blk-flush.c:518 [] blkdev_fsync+0x85/0xb0 fs/block_dev.c:378 [] vfs_fsync_range+0x10a/0x250 fs/sync.c:195 [] vfs_fsync fs/sync.c:209 [inline] [] do_fsync+0x42/0xb0 fs/sync.c:219 [] SYSC_fsync fs/sync.c:228 [inline] [] SyS_fsync+0x16/0x20 fs/sync.c:226 [] entry_SYSCALL_64_fastpath+0x23/0xc6 Showing all locks held in the system: 2 locks held by khungtaskd/514: #0: (rcu_read_lock){......}, at: [] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline] #0: (rcu_read_lock){......}, at: [] watchdog+0x125/0xa70 kernel/hung_task.c:239 #1: (tasklist_lock){.+.+..}, at: [] debug_show_all_locks+0x70/0x280 kernel/locking/lockdep.c:4336 1 lock held by rsyslogd/3157: #0: (&f->f_pos_lock){+.+.+.}, at: [] __fdget_pos+0x9f/0xc0 fs/file.c:781 2 locks held by getty/3285: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.+.}, at: [] n_tty_read+0x1f4/0x16c0 drivers/tty/n_tty.c:2133 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 514 Comm: khungtaskd Not tainted 4.9.69-g3f1d77c #108 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ffff8801d8937d00 ffffffff81d90a29 0000000000000000 0000000000000000 0000000000000000 0000000000000001 ffffffff810ba1a0 ffff8801d8937d38 ffffffff81d9bb4d 0000000000000000 0000000000000000 ffff8801a8a8b418 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] nmi_cpu_backtrace+0xfd/0x120 lib/nmi_backtrace.c:99 [] nmi_trigger_cpumask_backtrace+0x117/0x190 lib/nmi_backtrace.c:60 [] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [] check_hung_task kernel/hung_task.c:125 [inline] [] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline] [] watchdog+0x6f0/0xa70 kernel/hung_task.c:239 [] kthread+0x26d/0x300 kernel/kthread.c:211 [] ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:433 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff838a9766