INFO: task blkid:3090 blocked for more than 120 seconds. Not tainted 4.15.0-rc1-mm1+ #29 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. blkid D23696 3090 3062 0x00000004 Call Trace: context_switch kernel/sched/core.c:2800 [inline] __schedule+0x8eb/0x2060 kernel/sched/core.c:3376 schedule+0xf5/0x430 kernel/sched/core.c:3435 schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3493 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0xaad/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 __blkdev_get+0x158/0x10e0 fs/block_dev.c:1439 blkdev_get+0x3a1/0xad0 fs/block_dev.c:1591 blkdev_open+0x1e4/0x270 fs/block_dev.c:1749 do_dentry_open+0x682/0xd70 fs/open.c:752 vfs_open+0x107/0x230 fs/open.c:866 do_last fs/namei.c:3379 [inline] path_openat+0x1157/0x3530 fs/namei.c:3519 do_filp_open+0x25b/0x3b0 fs/namei.c:3554 do_sys_open+0x502/0x6d0 fs/open.c:1059 SYSC_open fs/open.c:1077 [inline] SyS_open+0x2d/0x40 fs/open.c:1072 entry_SYSCALL_64_fastpath+0x1f/0x96 RIP: 0033:0x7fe5c5bfc120 RSP: 002b:00007ffde0d34f08 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fe5c5bfc120 RDX: 00007ffde0d35f34 RSI: 0000000000000000 RDI: 00007ffde0d35f34 RBP: 0000000000000000 R08: 0000000000000078 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000211e030 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000005 Showing all locks held in the system: 2 locks held by khungtaskd/675: #0: (rcu_read_lock){....}, at: [<000000007fb79bbe>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<000000007fb79bbe>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<0000000035358c26>] debug_show_all_locks+0xd3/0x400 kernel/locking/lockdep.c:4554 1 lock held by rsyslogd/2973: #0: (&f->f_pos_lock){+.+.}, at: [<0000000001261d81>] __fdget_pos+0x131/0x1a0 fs/file.c:770 2 locks held by getty/3055: #0: (&tty->ldisc_sem){++++}, at: [<000000005cc11435>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000008d2b0f7>] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131 2 locks held by getty/3056: #0: (&tty->ldisc_sem){++++}, at: [<000000005cc11435>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000008d2b0f7>] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131 2 locks held by getty/3057: #0: (&tty->ldisc_sem){++++}, at: [<000000005cc11435>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000008d2b0f7>] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131 2 locks held by getty/3058: #0: (&tty->ldisc_sem){++++}, at: [<000000005cc11435>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000008d2b0f7>] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131 2 locks held by getty/3059: #0: (&tty->ldisc_sem){++++}, at: [<000000005cc11435>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000008d2b0f7>] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131 2 locks held by getty/3060: #0: (&tty->ldisc_sem){++++}, at: [<000000005cc11435>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000008d2b0f7>] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131 2 locks held by getty/3061: #0: (&tty->ldisc_sem){++++}, at: [<000000005cc11435>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<0000000008d2b0f7>] n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131 1 lock held by syzkaller346228/3087: #0: (&bdev->bd_mutex){+.+.}, at: [<0000000099fa8891>] __blkdev_put+0xa7/0x7c0 fs/block_dev.c:1757 1 lock held by blkid/3090: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000d4caea9e>] __blkdev_get+0x158/0x10e0 fs/block_dev.c:1439 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 675 Comm: khungtaskd Not tainted 4.15.0-rc1-mm1+ #29 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+0x37a/0x440 kernel/kthread.c:238 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:517 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.15.0-rc1-mm1+ #29 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: 0000000064c7084b task.stack: 00000000bb7e08d1 RIP: 0010:sched_ttwu_pending+0x0/0x270 kernel/sched/core.c:1584 RSP: 0018:ffff8801db507d68 EFLAGS: 00000046 RAX: 0000000000000003 RBX: 0000000000027900 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8801da3894a0 RBP: ffff8801db507e90 R08: 0000000000000001 R09: ffff88021fff8048 R10: ffff88021fff8050 R11: ffff88021fff805d R12: ffff8801da388300 R13: 1ffff1003b6a0fb1 R14: ffff8801db507e68 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8801db500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe5c5bfc110 CR3: 00000001d1b96000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: smp_reschedule_interrupt+0xe6/0x670 arch/x86/kernel/smp.c:277 reschedule_interrupt+0xa9/0xb0 arch/x86/entry/entry_64.S:931 RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54 RSP: 0018:ffff8801da397da8 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff02 RAX: dffffc0000000000 RBX: 1ffff1003b472fb8 RCX: 0000000000000000 RDX: 1ffffffff0bd9744 RSI: 0000000000000001 RDI: ffffffff85ecba20 RBP: ffff8801da397da8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: ffff8801da397e60 R14: ffffffff865eca20 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:93 [inline] default_idle+0xbf/0x430 arch/x86/kernel/process.c:355 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:346 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+0x18/0x20 kernel/sched/idle.c:351 start_secondary+0x2dd/0x3e0 arch/x86/kernel/smpboot.c:277 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:237 Code: ff ff 4c 89 85 70 ff ff ff e8 ad 12 5a 00 48 8b 95 68 ff ff ff 4c 8b 85 70 ff ff ff e9 19 fe ff ff 66 2e 0f 1f 84 00 00 00 00 00 <55> 48 89 e5 41 57 41 56 41 55 4c 8d ad 78 ff ff ff 49 be 00 00