INFO: task syz-executor5:12635 blocked for more than 140 seconds. Not tainted 4.19.0-rc5+ #31 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor5 D23536 12635 5522 0x00000004 Call Trace: context_switch kernel/sched/core.c:2825 [inline] __schedule+0x86c/0x1ed0 kernel/sched/core.c:3473 schedule+0xfe/0x460 kernel/sched/core.c:3517 schedule_timeout+0x1cc/0x260 kernel/time/timer.c:1780 io_schedule_timeout+0x26/0x80 kernel/sched/core.c:5128 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common_io kernel/sched/completion.c:121 [inline] wait_for_completion_io+0x427/0x8a0 kernel/sched/completion.c:169 submit_bio_wait+0x13c/0x1e0 block/bio.c:930 blkdev_issue_flush+0x204/0x300 block/blk-flush.c:553 blkdev_fsync+0x93/0xd0 fs/block_dev.c:633 vfs_fsync_range+0x140/0x220 fs/sync.c:197 vfs_fsync fs/sync.c:211 [inline] do_fsync+0x52/0xa0 fs/sync.c:221 __do_sys_fdatasync fs/sync.c:234 [inline] __se_sys_fdatasync fs/sync.c:232 [inline] __x64_sys_fdatasync+0x36/0x50 fs/sync.c:232 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457579 Code: 24 08 48 89 01 e8 d7 2d fc ff e8 22 7a fc ff b8 02 00 00 00 48 8d 0d 2a 8a 08 01 87 01 8b 05 22 8a 08 01 83 f8 01 0f 85 8a 00 <00> 00 b8 01 00 00 00 88 05 5e 8f 08 01 84 c0 74 72 b8 01 00 00 00 RSP: 002b:00007fbb7ffaac78 EFLAGS: 00000246 ORIG_RAX: 000000000000004b RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000457579 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fbb7ffab6d4 R13: 00000000004bdd86 R14: 00000000004ccad8 R15: 00000000ffffffff INFO: task syz-executor5:12697 blocked for more than 140 seconds. Not tainted 4.19.0-rc5+ #31 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor5 D25024 12697 5522 0x00000004 Call Trace: context_switch kernel/sched/core.c:2825 [inline] __schedule+0x86c/0x1ed0 kernel/sched/core.c:3473 schedule+0xfe/0x460 kernel/sched/core.c:3517 schedule_timeout+0x1cc/0x260 kernel/time/timer.c:1780 io_schedule_timeout+0x26/0x80 kernel/sched/core.c:5128 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common_io kernel/sched/completion.c:121 [inline] wait_for_completion_io+0x427/0x8a0 kernel/sched/completion.c:169 submit_bio_wait+0x13c/0x1e0 block/bio.c:930 blkdev_issue_flush+0x204/0x300 block/blk-flush.c:553 blkdev_fsync+0x93/0xd0 fs/block_dev.c:633 vfs_fsync_range+0x140/0x220 fs/sync.c:197 vfs_fsync fs/sync.c:211 [inline] do_fsync+0x52/0xa0 fs/sync.c:221 __do_sys_fdatasync fs/sync.c:234 [inline] __se_sys_fdatasync fs/sync.c:232 [inline] __x64_sys_fdatasync+0x36/0x50 fs/sync.c:232 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457579 Code: 24 08 48 89 01 e8 d7 2d fc ff e8 22 7a fc ff b8 02 00 00 00 48 8d 0d 2a 8a 08 01 87 01 8b 05 22 8a 08 01 83 f8 01 0f 85 8a 00 <00> 00 b8 01 00 00 00 88 05 5e 8f 08 01 84 c0 74 72 b8 01 00 00 00 RSP: 002b:00007fbb7ff68c78 EFLAGS: 00000246 ORIG_RAX: 000000000000004b RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000457579 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006 RBP: 000000000072c040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fbb7ff696d4 R13: 00000000004bdd86 R14: 00000000004ccad8 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/984: #0: 00000000344aae4e (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4435 1 lock held by rsyslogd/5253: #0: 00000000f0010ae6 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/5343: #0: 00000000eebba4ea (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000a604799a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5344: #0: 0000000022a4e3f8 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000071797031 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5345: #0: 00000000adc3b1bd (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000001a4dafc0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5346: #0: 00000000446a50cf (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000d4377994 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5347: #0: 00000000d367716d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000496e7576 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5348: #0: 0000000030b98324 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000003504f36a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/5349: #0: 00000000755bb6b4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000ea91ce60 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 984 Comm: khungtaskd Not tainted 4.19.0-rc5+ #31 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+0x1c4/0x2b4 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.3+0x63/0xa2 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/0x420 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413 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