Buffer I/O error on dev loop0, logical block 27, async page read Buffer I/O error on dev loop0, logical block 28, async page read Buffer I/O error on dev loop0, logical block 29, async page read Buffer I/O error on dev loop0, logical block 30, async page read Buffer I/O error on dev loop0, logical block 31, async page read INFO: task syz-executor0:8538 blocked for more than 120 seconds. Not tainted 4.16.0+ #15 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D21440 8538 8537 0x00000000 Call Trace: context_switch kernel/sched/core.c:2848 [inline] __schedule+0x8fb/0x1ef0 kernel/sched/core.c:3490 schedule+0xf5/0x430 kernel/sched/core.c:3549 schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3607 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0xb7f/0x1810 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 __blkdev_get+0x176/0x13b0 fs/block_dev.c:1458 blkdev_get+0x399/0xb00 fs/block_dev.c:1609 blkdev_open+0x1c9/0x250 fs/block_dev.c:1767 do_dentry_open+0x772/0xd70 fs/open.c:794 vfs_open+0x107/0x220 fs/open.c:908 do_last fs/namei.c:3372 [inline] path_openat+0x1151/0x3590 fs/namei.c:3512 do_filp_open+0x25b/0x3b0 fs/namei.c:3547 do_sys_open+0x502/0x6d0 fs/open.c:1101 SYSC_open fs/open.c:1119 [inline] SyS_open+0x2d/0x40 fs/open.c:1114 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x40f510 RSP: 002b:00007fffa24a0d88 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000042 RCX: 000000000040f510 RDX: 00007fffa24a1b4a RSI: 0000000000000002 RDI: 00007fffa24a1b40 RBP: 00007fffa24a0db0 R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000075 R11: 0000000000000246 R12: 0000000000000013 R13: 0000000000000000 R14: 00000000006fe780 R15: 0000000000001380 Showing all locks held in the system: 2 locks held by khungtaskd/877: #0: 00000000f6638189 (rcu_read_lock){....}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: 00000000f6638189 (rcu_read_lock){....}, at: watchdog+0x1d6/0xd70 kernel/hung_task.c:249 #1: 00000000f137ced5 (tasklist_lock){.+.+}, at: debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4470 1 lock held by rsyslogd/4332: #0: 000000008661241b (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x165/0x1a0 fs/file.c:766 2 locks held by getty/4422: #0: 000000003022fd3d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000e0d5855c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4423: #0: 00000000972b6f91 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000043667a18 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4424: #0: 000000001e373401 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000000e393666 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4425: #0: 00000000a6989a08 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000fcbcbe8c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4426: #0: 0000000004e4eacf (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000009cca8ff4 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4427: #0: 000000002e42e23e (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000008838040d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4428: #0: 000000008796698a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000035d003d3 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 3 locks held by kworker/u4:4/5878: #0: 000000009e246afc ((wq_completion)"writeback"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline] #0: 000000009e246afc ((wq_completion)"writeback"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000009e246afc ((wq_completion)"writeback"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 000000009e246afc ((wq_completion)"writeback"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:57 [inline] #0: 000000009e246afc ((wq_completion)"writeback"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 000000009e246afc ((wq_completion)"writeback"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 000000009e246afc ((wq_completion)"writeback"){+.+.}, at: process_one_work+0xb83/0x1c40 kernel/workqueue.c:2116 #1: 0000000087f4a28e ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0xbd9/0x1c40 kernel/workqueue.c:2120 #2: 00000000b544aa8a (&type->s_umount_key#35){++++}, at: trylock_super+0x20/0x100 fs/super.c:395 1 lock held by syz-executor0/8538: #0: 00000000dd579dc8 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x176/0x13b0 fs/block_dev.c:1458 1 lock held by blkid/11015: #0: 00000000dd579dc8 (&bdev->bd_mutex){+.+.}, at: blkdev_put+0x2a/0x4f0 fs/block_dev.c:1808 1 lock held by syz-executor3/11346: #0: 00000000dd579dc8 (&bdev->bd_mutex){+.+.}, at: iterate_bdevs+0xc8/0x260 fs/block_dev.c:2160 1 lock held by syz-executor3/11361: #0: 00000000dd579dc8 (&bdev->bd_mutex){+.+.}, at: iterate_bdevs+0xc8/0x260 fs/block_dev.c:2160 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 877 Comm: khungtaskd Not tainted 4.16.0+ #15 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+0x1a7/0x27d lib/dump_stack.c:53 nmi_cpu_backtrace+0x1e0/0x220 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+0x969/0xd70 kernel/hung_task.c:249 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54