Buffer I/O error on dev loop0, logical block 0, async page read INFO: task blkid:15350 blocked for more than 120 seconds. Not tainted 4.9.94-g8683408 #3 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. blkid D28232 15350 2223 0x00000006 ffff8801c1768000 ffff8801c63ca4c0 ffff8801cee45a40 ffff8801c60b6000 ffff8801db321b98 ffff8801cfd77310 ffffffff838c040d 0000000041b58ab3 ffffffff841a49d8 ffffffff81234350 00ff8801cfd774e8 ffff8801db322468 Call Trace: [] schedule+0x7f/0x1b0 kernel/sched/core.c:3557 [] schedule_timeout+0x861/0xf70 kernel/time/timer.c:1768 [] io_schedule_timeout+0x1ba/0x390 kernel/sched/core.c:5180 [] io_schedule include/linux/sched.h:460 [inline] [] bit_wait_io+0x19/0xa0 kernel/sched/wait.c:582 [] __wait_on_bit_lock+0xce/0x1c0 kernel/sched/wait.c:421 [] __lock_page+0xff/0x160 mm/filemap.c:934 [] lock_page include/linux/pagemap.h:454 [inline] [] truncate_inode_pages_range+0x818/0x1290 mm/truncate.c:373 [] truncate_inode_pages+0x24/0x30 mm/truncate.c:401 [] kill_bdev+0xbc/0xf0 fs/block_dev.c:96 [] __blkdev_put+0x1e3/0x840 fs/block_dev.c:1586 [] blkdev_put+0x85/0x560 fs/block_dev.c:1663 [] blkdev_close+0x8b/0xb0 fs/block_dev.c:1670 [] __fput+0x263/0x700 fs/file_table.c:208 [] ____fput+0x15/0x20 fs/file_table.c:244 [] task_work_run+0x10c/0x180 kernel/task_work.c:116 [] exit_task_work include/linux/task_work.h:21 [inline] [] do_exit+0x9e1/0x27c0 kernel/exit.c:837 [] do_group_exit+0x111/0x340 kernel/exit.c:941 [] get_signal+0x4cf/0x1450 kernel/signal.c:2317 [] do_signal+0x87/0x19f0 arch/x86/kernel/signal.c:807 [] exit_to_usermode_loop+0xe1/0x120 arch/x86/entry/common.c:157 [] prepare_exit_to_usermode arch/x86/entry/common.c:191 [inline] [] syscall_return_slowpath arch/x86/entry/common.c:260 [inline] [] do_syscall_64+0x364/0x490 arch/x86/entry/common.c:287 [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Showing all locks held in the system: 2 locks held by khungtaskd/515: #0: (rcu_read_lock){......}, at: [] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline] #0: (rcu_read_lock){......}, at: [] watchdog+0x11c/0xa20 kernel/hung_task.c:239 #1: (tasklist_lock){.+.+..}, at: [] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336 2 locks held by getty/3632: #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+0x202/0x16b0 drivers/tty/n_tty.c:2133 1 lock held by blkid/15350: #0: (&bdev->bd_mutex){+.+.+.}, at: [] __blkdev_put+0xbb/0x840 fs/block_dev.c:1579 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 515 Comm: khungtaskd Not tainted 4.9.94-g8683408 #3 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ffff8801d8707d08 ffffffff81d9b509 0000000000000000 0000000000000000 0000000000000000 0000000000000001 ffffffff810b7d60 ffff8801d8707d40 ffffffff81da6837 0000000000000000 0000000000000000 0000000000000002 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99 [] nmi_trigger_cpumask_backtrace+0x12a/0x14f 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+0x6b4/0xa20 kernel/hung_task.c:239 [] kthread+0x26d/0x300 kernel/kthread.c:211 [] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff838cff16