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 buffer_io_error: 118 callbacks suppressed Buffer I/O error on dev loop0, logical block 5120, async page read Buffer I/O error on dev loop2, logical block 2032, async page read INFO: task blkid:23906 blocked for more than 120 seconds. Not tainted 4.16.0+ #19 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. blkid D22616 23906 6848 0x80000006 Call Trace: context_switch kernel/sched/core.c:2848 [inline] __schedule+0x807/0x1e40 kernel/sched/core.c:3490 schedule+0xef/0x430 kernel/sched/core.c:3549 schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3607 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0xe38/0x17f0 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 blkdev_put+0x34/0x540 fs/block_dev.c:1810 blkdev_close+0x8b/0xb0 fs/block_dev.c:1859 __fput+0x34d/0x890 fs/file_table.c:209 ____fput+0x15/0x20 fs/file_table.c:243 task_work_run+0x1e4/0x290 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x1aee/0x2730 kernel/exit.c:865 do_group_exit+0x16f/0x430 kernel/exit.c:968 get_signal+0x886/0x1960 kernel/signal.c:2469 do_signal+0x98/0x2040 arch/x86/kernel/signal.c:810 exit_to_usermode_loop+0x28a/0x310 arch/x86/entry/common.c:162 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline] syscall_return_slowpath arch/x86/entry/common.c:265 [inline] do_syscall_64+0x792/0x9d0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x7f1f0114f310 RSP: 002b:00007ffefc1017d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: fffffffffffffffb RBX: 0000000001400000 RCX: 00007f1f0114f310 RDX: 0000000000000040 RSI: 0000000000e5fc58 RDI: 0000000000000003 RBP: 0000000000e5fc30 R08: 0000000000000068 R09: 0101010101010101 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000e5f030 R13: 0000000000000040 R14: 0000000000e5f080 R15: 0000000000e5fc48 Showing all locks held in the system: 2 locks held by khungtaskd/887: #0: 0000000061b513be (rcu_read_lock){....}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: 0000000061b513be (rcu_read_lock){....}, at: watchdog+0x1ff/0xf60 kernel/hung_task.c:249 #1: 000000001b28a052 (tasklist_lock){.+.+}, at: debug_show_all_locks+0xde/0x34a kernel/locking/lockdep.c:4470 2 locks held by getty/4399: #0: 00000000be630595 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000f5826a10 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4400: #0: 0000000006589210 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000aace9728 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4401: #0: 0000000033e5fbd5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000c6c765bb (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4402: #0: 00000000506e9350 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000006fa4df2c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4403: #0: 00000000154eff06 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000dcda197d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4404: #0: 0000000057845e2a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000007e6cda87 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/19553: #0: 00000000fd798373 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000008140ffda (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 1 lock held by blkid/23906: #0: 00000000e50f3e64 (&bdev->bd_mutex){+.+.}, at: blkdev_put+0x34/0x540 fs/block_dev.c:1810 3 locks held by kworker/u4:2/25154: #0: 0000000011fc89ab ((wq_completion)"writeback"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline] #0: 0000000011fc89ab ((wq_completion)"writeback"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 0000000011fc89ab ((wq_completion)"writeback"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 0000000011fc89ab ((wq_completion)"writeback"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:57 [inline] #0: 0000000011fc89ab ((wq_completion)"writeback"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 0000000011fc89ab ((wq_completion)"writeback"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 0000000011fc89ab ((wq_completion)"writeback"){+.+.}, at: process_one_work+0xaef/0x1b50 kernel/workqueue.c:2116 #1: 00000000623a2ca4 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0xb46/0x1b50 kernel/workqueue.c:2120 #2: 00000000eee4c089 (&type->s_umount_key#35){.+.+}, at: trylock_super+0x22/0x110 fs/super.c:395 1 lock held by syz-executor3/25862: #0: 00000000e50f3e64 (&bdev->bd_mutex){+.+.}, at: blkdev_put+0x34/0x540 fs/block_dev.c:1810 1 lock held by syz-executor3/25888: #0: 00000000e50f3e64 (&bdev->bd_mutex){+.+.}, at: iterate_bdevs+0xce/0x291 fs/block_dev.c:2157 1 lock held by syz-executor3/25890: #0: 00000000e50f3e64 (&bdev->bd_mutex){+.+.}, at: iterate_bdevs+0xce/0x291 fs/block_dev.c:2157 1 lock held by syz-executor3/25893: #0: 00000000e50f3e64 (&bdev->bd_mutex){+.+.}, at: iterate_bdevs+0xce/0x291 fs/block_dev.c:2157 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 887 Comm: khungtaskd Not tainted 4.16.0+ #19 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+0x1b9/0x294 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x151/0x192 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+0xc10/0xf60 kernel/hung_task.c:249 kthread+0x345/0x410 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