323571 pages reserved Buffer I/O error on dev loop0, logical block 3, async page read INFO: task blkid:12792 blocked for more than 120 seconds. Not tainted 4.13.0-rc5-next-20170817+ #5 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. blkid D21072 12792 1638 0x80000006 Call Trace: context_switch kernel/sched/core.c:2786 [inline] __schedule+0x8e8/0x2070 kernel/sched/core.c:3362 schedule+0x108/0x440 kernel/sched/core.c:3421 schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3479 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0xadf/0x1870 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 blkdev_put+0x2a/0x4f0 fs/block_dev.c:1800 blkdev_close+0x8b/0xb0 fs/block_dev.c:1849 __fput+0x327/0x7e0 fs/file_table.c:210 ____fput+0x15/0x20 fs/file_table.c:246 task_work_run+0x199/0x270 kernel/task_work.c:112 exit_task_work include/linux/task_work.h:21 [inline] do_exit+0xa52/0x1b30 kernel/exit.c:865 do_group_exit+0x149/0x400 kernel/exit.c:968 get_signal+0x7e8/0x17e0 kernel/signal.c:2330 do_signal+0x94/0x1ee0 arch/x86/kernel/signal.c:808 exit_to_usermode_loop+0x224/0x300 arch/x86/entry/common.c:158 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath+0x42f/0x500 arch/x86/entry/common.c:266 entry_SYSCALL_64_fastpath+0xbc/0xbe RIP: 0033:0x7f2c67131310 RSP: 002b:00007ffd450a7328 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: fffffffffffffffb RBX: 0000000000003e00 RCX: 00007f2c67131310 RDX: 0000000000000200 RSI: 0000000001770088 RDI: 0000000000000003 RBP: 0000000001770060 R08: 0000000000000028 R09: 0000000000168000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000176f030 R13: 0000000000000200 R14: 000000000176f080 R15: 0000000001770078 Showing all locks held in the system: 2 locks held by khungtaskd/639: #0: (rcu_read_lock){....}, at: [] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.?.+}, at: [] debug_show_all_locks+0xd2/0x410 kernel/locking/lockdep.c:4552 2 locks held by getty/2998: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/2999: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/3000: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/3001: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/3002: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/3003: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/3004: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.}, at: [] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2133 3 locks held by kworker/u4:7/5839: #0: ("writeback"){.+.+}, at: [] __write_once_size include/linux/compiler.h:305 [inline] #0: ("writeback"){.+.+}, at: [] atomic64_set arch/x86/include/asm/atomic64_64.h:33 [inline] #0: ("writeback"){.+.+}, at: [] atomic_long_set include/asm-generic/atomic-long.h:56 [inline] #0: ("writeback"){.+.+}, at: [] set_work_data kernel/workqueue.c:617 [inline] #0: ("writeback"){.+.+}, at: [] set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: ("writeback"){.+.+}, at: [] process_one_work+0xadf/0x1bc0 kernel/workqueue.c:2090 #1: ((&(&wb->dwork)->work)){+.+.}, at: [] process_one_work+0xb32/0x1bc0 kernel/workqueue.c:2094 #2: (&type->s_umount_key#30){.+.+}, at: [] trylock_super+0x20/0x100 fs/super.c:391 1 lock held by blkid/12792: #0: (&bdev->bd_mutex){+.+.}, at: [] blkdev_put+0x2a/0x4f0 fs/block_dev.c:1800 1 lock held by syz-executor4/14261: #0: (&bdev->bd_mutex){+.+.}, at: [] iterate_bdevs+0xc8/0x260 fs/block_dev.c:2149 1 lock held by syz-executor4/14268: #0: (&bdev->bd_mutex){+.+.}, at: [] iterate_bdevs+0xc8/0x260 fs/block_dev.c:2149 1 lock held by syz-executor3/14283: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x158/0xf60 fs/block_dev.c:1449 1 lock held by syz-executor3/14294: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x158/0xf60 fs/block_dev.c:1449 1 lock held by syz-executor7/14307: #0: (&bdev->bd_mutex){+.+.}, at: [] iterate_bdevs+0xc8/0x260 fs/block_dev.c:2149 1 lock held by syz-executor7/14320: #0: (&bdev->bd_mutex){+.+.}, at: [] iterate_bdevs+0xc8/0x260 fs/block_dev.c:2149 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 639 Comm: khungtaskd Not tainted 4.13.0-rc5-next-20170817+ #5 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:52 nmi_cpu_backtrace+0x20e/0x240 lib/nmi_backtrace.c:102 nmi_trigger_cpumask_backtrace+0x122/0x180 lib/nmi_backtrace.c:61 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 trigger_all_cpu_backtrace include/linux/nmi.h:105 [inline] check_hung_task kernel/hung_task.c:132 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline] watchdog+0x90c/0xd60 kernel/hung_task.c:249 kthread+0x35e/0x430 kernel/kthread.c:231 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff84d71e36