Buffer I/O error on dev loop0, logical block 3, async page read INFO: task syz-executor1:7786 blocked for more than 120 seconds. Not tainted 4.13.0+ #72 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor1 D23064 7786 3057 0x00000004 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 io_schedule+0x1c/0x70 kernel/sched/core.c:5028 wait_on_page_bit_common+0x48f/0x730 mm/filemap.c:974 wait_on_page_bit mm/filemap.c:1007 [inline] wait_on_page_writeback include/linux/pagemap.h:541 [inline] __filemap_fdatawait_range+0x2b3/0x460 mm/filemap.c:436 filemap_fdatawait_keep_errors+0x2a/0xb0 mm/filemap.c:503 fdatawait_one_bdev+0x50/0x70 fs/sync.c:94 iterate_bdevs+0x109/0x260 fs/block_dev.c:2151 sys_sync+0x122/0x1c0 fs/sync.c:116 entry_SYSCALL_64_fastpath+0x1f/0xbe RIP: 0033:0x451e59 RSP: 002b:00007fdd2a6eec08 EFLAGS: 00000216 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 0000000000718000 RCX: 0000000000451e59 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000082 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000216 R12: 0000000000000000 R13: 0000000000a6f7ef R14: 00007fdd2a6ef9c0 R15: 0000000000000000 Showing all locks held in the system: 2 locks held by khungtaskd/641: #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/2951: #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+0x2f2/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/2952: #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+0x2f2/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/2953: #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+0x2f2/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/2954: #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+0x2f2/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/2955: #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+0x2f2/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/2956: #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+0x2f2/0x1a40 drivers/tty/n_tty.c:2133 2 locks held by getty/2957: #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+0x2f2/0x1a40 drivers/tty/n_tty.c:2133 3 locks held by kworker/u4:6/3900: #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+0xad4/0x1bd0 kernel/workqueue.c:2090 #1: ((&(&wb->dwork)->work)){+.+.}, at: [] process_one_work+0xb2c/0x1bd0 kernel/workqueue.c:2094 #2: (&type->s_umount_key#30){.+.+}, at: [] trylock_super+0x20/0x100 fs/super.c:391 1 lock held by blkid/7649: #0: (&bdev->bd_mutex){+.+.}, at: [] blkdev_put+0x2a/0x4f0 fs/block_dev.c:1800 1 lock held by syz-executor1/7786: #0: (&bdev->bd_mutex){+.+.}, at: [] iterate_bdevs+0xc8/0x260 fs/block_dev.c:2149 1 lock held by syz-executor1/7795: #0: (&bdev->bd_mutex){+.+.}, at: [] iterate_bdevs+0xc8/0x260 fs/block_dev.c:2149 1 lock held by syz-executor0/7856: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x158/0xf60 fs/block_dev.c:1449 1 lock held by syz-executor0/7859: #0: (&bdev->bd_mutex){+.+.}, at: [] __blkdev_get+0x158/0xf60 fs/block_dev.c:1449 1 lock held by syz-executor3/7874: #0: (&bdev->bd_mutex){+.+.}, at: [] iterate_bdevs+0xc8/0x260 fs/block_dev.c:2149 1 lock held by syz-executor3/7880: #0: (&bdev->bd_mutex){+.+.}, at: [] iterate_bdevs+0xc8/0x260 fs/block_dev.c:2149 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 641 Comm: khungtaskd Not tainted 4.13.0+ #72 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+0x39c/0x470 kernel/kthread.c:231 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff84d177d6