Buffer I/O error on dev loop0, logical block 0, lost async page write INFO: task blkid:18996 blocked for more than 120 seconds. Not tainted 4.15.0+ #297 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. blkid D22432 18996 4159 0x00000004 Call Trace: context_switch kernel/sched/core.c:2845 [inline] __schedule+0x8eb/0x2060 kernel/sched/core.c:3421 schedule+0xf5/0x430 kernel/sched/core.c:3480 io_schedule+0x1c/0x70 kernel/sched/core.c:5096 wait_on_page_bit_common mm/filemap.c:1099 [inline] __lock_page+0x574/0x720 mm/filemap.c:1272 lock_page include/linux/pagemap.h:483 [inline] write_cache_pages+0xb32/0x14b0 mm/page-writeback.c:2206 generic_writepages+0xe9/0x150 mm/page-writeback.c:2325 blkdev_writepages+0x1d/0x30 fs/block_dev.c:1939 do_writepages+0xff/0x170 mm/page-writeback.c:2340 __filemap_fdatawrite_range+0x32f/0x460 mm/filemap.c:444 __filemap_fdatawrite mm/filemap.c:452 [inline] filemap_fdatawrite mm/filemap.c:457 [inline] filemap_write_and_wait+0x59/0xd0 mm/filemap.c:616 __sync_blockdev fs/block_dev.c:448 [inline] sync_blockdev.part.29+0x50/0x70 fs/block_dev.c:457 sync_blockdev fs/block_dev.c:444 [inline] __blkdev_put+0x18b/0x7f0 fs/block_dev.c:1763 blkdev_put+0x85/0x4f0 fs/block_dev.c:1835 blkdev_close+0x8b/0xb0 fs/block_dev.c:1842 __fput+0x327/0x7e0 fs/file_table.c:209 ____fput+0x15/0x20 fs/file_table.c:243 task_work_run+0x199/0x270 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x275/0x2f0 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline] syscall_return_slowpath arch/x86/entry/common.c:265 [inline] do_syscall_64+0x6ed/0x940 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x26/0x9b RIP: 0033:0x7fad80ec02b0 RSP: 002b:00007ffe54428d58 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fad80ec02b0 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000028 R09: 0000000001680000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000007d4030 R13: 0000000000000000 R14: 0000000000000003 R15: 0000000000000005 Showing all locks held in the system: 3 locks held by kworker/u4:1/21: #0: ((wq_completion)"writeback"){+.+.}, at: [<00000000b3e2d4e9>] process_one_work+0xaaf/0x1af0 kernel/workqueue.c:2084 #1: ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: [<00000000d1e40742>] process_one_work+0xb01/0x1af0 kernel/workqueue.c:2088 #2: (&type->s_umount_key#27){++++}, at: [<000000000e2fc77c>] trylock_super+0x20/0x100 fs/super.c:395 2 locks held by khungtaskd/756: #0: (rcu_read_lock){....}, at: [<00000000f79e0e80>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<00000000f79e0e80>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<000000005d3d9da6>] debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4470 2 locks held by getty/4150: #0: (&tty->ldisc_sem){++++}, at: [<000000005dc93adc>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000031e79500>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4151: #0: (&tty->ldisc_sem){++++}, at: [<000000005dc93adc>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000031e79500>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4152: #0: (&tty->ldisc_sem){++++}, at: [<000000005dc93adc>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000031e79500>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4153: #0: (&tty->ldisc_sem){++++}, at: [<000000005dc93adc>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000031e79500>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4154: #0: (&tty->ldisc_sem){++++}, at: [<000000005dc93adc>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000031e79500>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4155: #0: (&tty->ldisc_sem){++++}, at: [<000000005dc93adc>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000031e79500>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4156: #0: (&tty->ldisc_sem){++++}, at: [<000000005dc93adc>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000031e79500>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 1 lock held by blkid/18996: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000a934127e>] __blkdev_put+0xbc/0x7f0 fs/block_dev.c:1757 1 lock held by syz-executor7/19032: #0: (&bdev->bd_mutex){+.+.}, at: [<0000000050610829>] __blkdev_get+0x158/0x10e0 fs/block_dev.c:1439 1 lock held by syz-executor7/19046: #0: (&bdev->bd_mutex){+.+.}, at: [<0000000050610829>] __blkdev_get+0x158/0x10e0 fs/block_dev.c:1439 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 756 Comm: khungtaskd Not tainted 4.15.0+ #297 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+0x194/0x257 lib/dump_stack.c:53 nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x122/0x180 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+0x90c/0xd60 kernel/hung_task.c:249 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:429 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.15.0+ #297 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__pvclock_read_cycles arch/x86/include/asm/pvclock.h:86 [inline] RIP: 0010:pvclock_clocksource_read+0xff/0x680 arch/x86/kernel/pvclock.c:87 RSP: 0018:ffff8801db407b20 EFLAGS: 00000082 RAX: ffff88021fff801c RBX: ffff88021fff8000 RCX: 0000000000000008 RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff88021fff8000 RBP: ffff8801db407c10 R08: ffff88021fff801c R09: ffff88021fff8008 R10: ffff88021fff8010 R11: ffff88021fff801d R12: dffffc0000000000 R13: 1ffff1003b680f71 R14: ffff88021fff8003 R15: ffffed0043fff001 FS: 0000000000000000(0000) GS:ffff8801db400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f50e49fb000 CR3: 0000000006a22006 CR4: 00000000001606f0 DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: kvm_clock_read arch/x86/kernel/kvmclock.c:89 [inline] kvm_clock_get_cycles+0x25/0x30 arch/x86/kernel/kvmclock.c:96 tk_clock_read kernel/time/timekeeping.c:161 [inline] timekeeping_get_delta kernel/time/timekeeping.c:255 [inline] timekeeping_get_ns kernel/time/timekeeping.c:361 [inline] ktime_get+0x20c/0x3a0 kernel/time/timekeeping.c:764 tick_nohz_irq_enter kernel/time/tick-sched.c:1148 [inline] tick_irq_enter+0x9e/0x390 kernel/time/tick-sched.c:1169 irq_enter+0xb6/0xd0 kernel/softirq.c:346 scheduler_ipi+0x23d/0x820 kernel/sched/core.c:1794 smp_reschedule_interrupt+0xe6/0x670 arch/x86/kernel/smp.c:277 reschedule_interrupt+0xa9/0xb0 arch/x86/entry/entry_64.S:849 RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54 RSP: 0018:ffffffff86a07c38 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff02 RAX: dffffc0000000000 RBX: 1ffffffff0d40f8a RCX: 0000000000000000 RDX: 1ffffffff0d59278 RSI: 0000000000000001 RDI: ffffffff86ac93c0 RBP: ffffffff86a07c38 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff86a07cf0 R14: ffffffff87268da0 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:93 [inline] default_idle+0xbf/0x430 arch/x86/kernel/process.c:354 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:345 default_idle_call+0x36/0x90 kernel/sched/idle.c:98 cpuidle_idle_call kernel/sched/idle.c:156 [inline] do_idle+0x24a/0x3b0 kernel/sched/idle.c:246 cpu_startup_entry+0x104/0x120 kernel/sched/idle.c:351 rest_init+0xed/0xf0 init/main.c:436 start_kernel+0x7f1/0x819 init/main.c:716 x86_64_start_reservations+0x2a/0x2c arch/x86/kernel/head64.c:378 x86_64_start_kernel+0x77/0x7a arch/x86/kernel/head64.c:359 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:237 Code: 49 c1 ef 03 4c 8d 5b 1d 48 89 85 58 ff ff ff 48 8d 43 1b 4d 01 e7 48 89 85 70 ff ff ff 48 8d 43 17 48 89 85 40 ff ff ff 4c 89 c0 <48> c1 e8 03 4c 01 e0 48 89 85 50 ff ff ff 83 e1 fe 89 8d 60 ff