Buffer I/O error on dev loop0, logical block 5, lost async page write Buffer I/O error on dev loop0, logical block 6, lost async page write Buffer I/O error on dev loop0, logical block 7, lost async page write Buffer I/O error on dev loop0, logical block 8, lost async page write Buffer I/O error on dev loop0, logical block 9, lost async page write INFO: task syz-executor0:22642 blocked for more than 120 seconds. Not tainted 4.16.0+ #288 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D23168 22642 4496 0x20020004 Call Trace: context_switch kernel/sched/core.c:2848 [inline] __schedule+0x8fb/0x1ef0 kernel/sched/core.c:3490 schedule+0xf5/0x430 kernel/sched/core.c:3549 io_schedule+0x1c/0x70 kernel/sched/core.c:5169 wait_on_page_bit_common+0x4b3/0x770 mm/filemap.c:1099 wait_on_page_bit mm/filemap.c:1132 [inline] wait_on_page_writeback include/linux/pagemap.h:546 [inline] __filemap_fdatawait_range+0x282/0x430 mm/filemap.c:533 file_write_and_wait_range+0xd7/0x100 mm/filemap.c:756 blkdev_fsync+0x67/0xb0 fs/block_dev.c:623 vfs_fsync_range+0x110/0x260 fs/sync.c:201 generic_write_sync include/linux/fs.h:2680 [inline] blkdev_write_iter+0x2e6/0x3e0 fs/block_dev.c:1910 call_write_iter include/linux/fs.h:1782 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x684/0x970 fs/read_write.c:487 vfs_write+0x189/0x510 fs/read_write.c:549 ksys_write+0xef/0x220 fs/read_write.c:598 SYSC_write fs/read_write.c:610 [inline] SyS_write+0x24/0x30 fs/read_write.c:607 do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline] do_fast_syscall_32+0x3ec/0xf9f arch/x86/entry/common.c:392 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f77c99 RSP: 002b:00000000f5f730ac EFLAGS: 00000282 ORIG_RAX: 0000000000000004 RAX: ffffffffffffffda RBX: 0000000000000014 RCX: 0000000020000280 RDX: 00000000fffffe60 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 2 locks held by khungtaskd/878: #0: 00000000c6f9461f (rcu_read_lock){....}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: 00000000c6f9461f (rcu_read_lock){....}, at: watchdog+0x1d6/0xd70 kernel/hung_task.c:249 #1: 00000000b9483b7d (tasklist_lock){.+.+}, at: debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4470 1 lock held by rsyslogd/4328: #0: 000000000875d8b7 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x165/0x1a0 fs/file.c:766 2 locks held by getty/4420: #0: 00000000e2a49bcd (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000079404cb3 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4421: #0: 0000000007cbe040 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000076205985 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4422: #0: 0000000031ec0e93 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000000c6eb85c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4423: #0: 0000000038d95749 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000615a607f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4424: #0: 000000003b7c2901 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000015b9146d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4425: #0: 000000002a3d259a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000003495998a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/28919: #0: 00000000ee051518 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000005376e1a8 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 3 locks held by kworker/u4:6/1431: #0: 00000000b162be59 ((wq_completion)"writeback"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline] #0: 00000000b162be59 ((wq_completion)"writeback"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000b162be59 ((wq_completion)"writeback"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000b162be59 ((wq_completion)"writeback"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:57 [inline] #0: 00000000b162be59 ((wq_completion)"writeback"){+.+.}, at: set_work_data kernel/workqueue.c:619 [inline] #0: 00000000b162be59 ((wq_completion)"writeback"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: 00000000b162be59 ((wq_completion)"writeback"){+.+.}, at: process_one_work+0xb83/0x1c40 kernel/workqueue.c:2084 #1: 00000000b87527d0 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0xbd9/0x1c40 kernel/workqueue.c:2088 #2: 0000000062286656 (&type->s_umount_key#35){++++}, at: trylock_super+0x20/0x100 fs/super.c:395 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 878 Comm: khungtaskd Not tainted 4.16.0+ #288 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+0x1a7/0x27d lib/dump_stack.c:53 nmi_cpu_backtrace+0x1e0/0x220 lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x123/0x180 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+0x969/0xd70 kernel/hung_task.c:249 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411 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:54