INFO: task blkid:24012 blocked for more than 120 seconds. Not tainted 4.16.0-rc6+ #270 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. blkid D21080 24012 4217 0x80000006 Call Trace: context_switch kernel/sched/core.c:2862 [inline] __schedule+0x8fb/0x1ec0 kernel/sched/core.c:3440 schedule+0xf5/0x430 kernel/sched/core.c:3499 io_schedule+0x1c/0x70 kernel/sched/core.c:5115 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 filemap_fdatawait_range mm/filemap.c:558 [inline] filemap_fdatawait include/linux/fs.h:2591 [inline] filemap_write_and_wait+0x7a/0xd0 mm/filemap.c:624 __sync_blockdev fs/block_dev.c:448 [inline] sync_blockdev.part.30+0x50/0x70 fs/block_dev.c:457 sync_blockdev fs/block_dev.c:444 [inline] __blkdev_put+0x18b/0x760 fs/block_dev.c:1781 blkdev_put+0x85/0x4f0 fs/block_dev.c:1850 blkdev_close+0x8b/0xb0 fs/block_dev.c:1857 __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 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x9bb/0x1ad0 kernel/exit.c:865 do_group_exit+0x149/0x400 kernel/exit.c:968 get_signal+0x73a/0x16d0 kernel/signal.c:2469 do_signal+0x90/0x1e90 arch/x86/kernel/signal.c:809 exit_to_usermode_loop+0x258/0x2f0 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+0x6ec/0x940 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x7f6e8d488310 RSP: 002b:00007fff0c86e6e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: fffffffffffffffb RBX: 0000000000010000 RCX: 00007f6e8d488310 RDX: 0000000000000561 RSI: 0000000002313b48 RDI: 0000000000000003 RBP: 0000000002313b20 R08: 0000000000000018 R09: 0000000001680000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000002310030 R13: 0000000000000561 R14: 0000000002310080 R15: 0000000002313b38 Showing all locks held in the system: 3 locks held by kworker/u4:1/21: #0: ((wq_completion)"writeback"){+.+.}, at: [<00000000e33f15e6>] work_static include/linux/workqueue.h:198 [inline] #0: ((wq_completion)"writeback"){+.+.}, at: [<00000000e33f15e6>] set_work_data kernel/workqueue.c:619 [inline] #0: ((wq_completion)"writeback"){+.+.}, at: [<00000000e33f15e6>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: ((wq_completion)"writeback"){+.+.}, at: [<00000000e33f15e6>] process_one_work+0xb12/0x1bb0 kernel/workqueue.c:2084 #1: ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: [<000000005fdc15c2>] process_one_work+0xb89/0x1bb0 kernel/workqueue.c:2088 #2: (&type->s_umount_key#27){++++}, at: [<000000007f7171de>] trylock_super+0x20/0x100 fs/super.c:395 2 locks held by khungtaskd/801: #0: (rcu_read_lock){....}, at: [<000000007c9b7a2f>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<000000007c9b7a2f>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<00000000ffab5fa4>] debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4470 2 locks held by getty/4209: #0: (&tty->ldisc_sem){++++}, at: [<000000005d3091a4>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000002f1328b2>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4210: #0: (&tty->ldisc_sem){++++}, at: [<000000005d3091a4>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000002f1328b2>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4211: #0: (&tty->ldisc_sem){++++}, at: [<000000005d3091a4>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000002f1328b2>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4212: #0: (&tty->ldisc_sem){++++}, at: [<000000005d3091a4>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000002f1328b2>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4213: #0: (&tty->ldisc_sem){++++}, at: [<000000005d3091a4>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000002f1328b2>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4214: #0: (&tty->ldisc_sem){++++}, at: [<000000005d3091a4>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000002f1328b2>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4215: #0: (&tty->ldisc_sem){++++}, at: [<000000005d3091a4>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000002f1328b2>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 1 lock held by blkid/24012: #0: (&bdev->bd_mutex){+.+.}, at: [<000000008197be44>] __blkdev_put+0xbc/0x760 fs/block_dev.c:1775 1 lock held by syz-executor0/31086: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000d9dfb5c1>] __blkdev_get+0x176/0x13b0 fs/block_dev.c:1458 1 lock held by syz-executor0/31088: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000d9dfb5c1>] __blkdev_get+0x176/0x13b0 fs/block_dev.c:1458 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 801 Comm: khungtaskd Not tainted 4.16.0-rc6+ #270 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+0x194/0x24d lib/dump_stack.c:53 nmi_cpu_backtrace+0x1d2/0x210 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+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:406 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.16.0-rc6+ #270 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:lockdep_init_map+0x0/0x10 kernel/locking/lockdep.c:3199 RSP: 0018:ffff8801db2071e8 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: ffff8801d42a35c0 RCX: 0000000000000000 RDX: ffffffff886116a0 RSI: ffffffff863f6520 RDI: ffff8801d42a36a0 RBP: ffff8801db2072c0 R08: ffff88021fff801c R09: ffff88021fff8008 R10: ffff88021fff8010 R11: ffff88021fff801d R12: 1ffff1003b640e3f R13: ffff8801d42a3698 R14: ffff8801db207298 R15: 1ffff1003b640e43 FS: 0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 0000000006e22002 CR4: 00000000001606f0 DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: blk_kick_flush block/blk-flush.c:323 [inline] blk_flush_complete_seq+0x75f/0x17b0 block/blk-flush.c:215 flush_data_end_io+0x1eb/0x320 block/blk-flush.c:395 blk_finish_request+0x3dd/0x670 block/blk-core.c:3107 scsi_end_request+0x3d3/0x820 drivers/scsi/scsi_lib.c:703 scsi_io_completion+0x8ab/0x16b0 drivers/scsi/scsi_lib.c:868 scsi_finish_command+0x5f6/0x890 drivers/scsi/scsi.c:248 scsi_softirq_done+0x3ab/0x480 drivers/scsi/scsi_lib.c:1653 blk_done_softirq+0x486/0x700 block/blk-softirq.c:37 __do_softirq+0x2d7/0xb85 kernel/softirq.c:285 invoke_softirq kernel/softirq.c:365 [inline] irq_exit+0x1cc/0x200 kernel/softirq.c:405 exiting_irq arch/x86/include/asm/apic.h:541 [inline] do_IRQ+0xeb/0x190 arch/x86/kernel/irq.c:250 common_interrupt+0xf/0xf arch/x86/entry/entry_64.S:636 RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54 RSP: 0018:ffffffff86e07c38 EFLAGS: 00000282 ORIG_RAX: ffffffffffffffda RAX: dffffc0000000000 RBX: 1ffffffff0dc0f8a RCX: 0000000000000000 RDX: 1ffffffff0dd93a0 RSI: 0000000000000001 RDI: ffffffff86ec9d00 RBP: ffffffff86e07c38 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff86e07cf0 R14: ffffffff876e80a0 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:94 [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:437 start_kernel+0x7f1/0x819 init/main.c:717 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:239 Code: 48 89 75 d8 e8 52 d6 52 00 48 8b 75 d8 e9 98 fa ff ff 48 89 75 d8 e8 40 d6 52 00 48 8b 75 d8 e9 f8 fc ff ff 0f 1f 80 00 00 00 00 <55> 48 89 e5 e8 a7 f9 ff ff 5d c3 0f 1f 44 00 00 55 49 89 f0 31