Buffer I/O error on dev loop0, logical block 1, async page read Buffer I/O error on dev loop0, logical block 3, async page read INFO: task syz-executor5:9424 blocked for more than 120 seconds. Not tainted 4.16.0+ #2 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor5 D23624 9424 4512 0x00000004 Call Trace: context_switch kernel/sched/core.c:2848 [inline] __schedule+0x807/0x1e40 kernel/sched/core.c:3490 schedule+0xef/0x430 kernel/sched/core.c:3549 io_schedule+0x1c/0x70 kernel/sched/core.c:5169 wait_on_page_bit_common+0x4dc/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+0x31e/0x4c0 mm/filemap.c:533 filemap_fdatawait_keep_errors+0x2d/0xc0 mm/filemap.c:600 fdatawait_one_bdev+0x50/0x70 fs/sync.c:95 iterate_bdevs+0x11e/0x291 fs/block_dev.c:2162 ksys_sync+0x122/0x1d0 fs/sync.c:117 sys_sync+0xe/0x20 fs/sync.c:124 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x4552d9 RSP: 002b:00007fb4d8ad1c68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007fb4d8ad26d4 RCX: 00000000004552d9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 000000000072bf58 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000064b R14: 00000000006fc7a8 R15: 0000000000000001 Showing all locks held in the system: 2 locks held by khungtaskd/878: #0: 000000009a210c5f (rcu_read_lock){....}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: 000000009a210c5f (rcu_read_lock){....}, at: watchdog+0x1ff/0xf60 kernel/hung_task.c:249 #1: 00000000b73dbac3 (tasklist_lock){.+.+}, at: debug_show_all_locks+0xde/0x34a kernel/locking/lockdep.c:4470 1 lock held by rsyslogd/4345: #0: 00000000c0f3b504 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1a9/0x1e0 fs/file.c:766 2 locks held by getty/4436: #0: 0000000014c2ae77 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000023d114fa (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4437: #0: 00000000be8321a2 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000008e238a88 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4438: #0: 0000000037fb47a5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000971cf4b2 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4439: #0: 0000000033780be8 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000004d49cf69 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4440: #0: 000000003a7c2dce (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000de293306 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4441: #0: 00000000851ba22f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000008ee9e288 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/17049: #0: 00000000ea403f57 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000002bbe0723 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 3 locks held by kworker/u4:2/1471: #0: 0000000076d7abd0 ((wq_completion)"writeback"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline] #0: 0000000076d7abd0 ((wq_completion)"writeback"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 0000000076d7abd0 ((wq_completion)"writeback"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 0000000076d7abd0 ((wq_completion)"writeback"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:57 [inline] #0: 0000000076d7abd0 ((wq_completion)"writeback"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 0000000076d7abd0 ((wq_completion)"writeback"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 0000000076d7abd0 ((wq_completion)"writeback"){+.+.}, at: process_one_work+0xaef/0x1b50 kernel/workqueue.c:2116 #1: 000000007fd05b4c ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0xb46/0x1b50 kernel/workqueue.c:2120 #2: 000000008e2c3c02 (&type->s_umount_key#35){++++}, at: trylock_super+0x22/0x110 fs/super.c:395 1 lock held by blkid/9383: #0: 00000000c0095b50 (&bdev->bd_mutex){+.+.}, at: blkdev_put+0x34/0x540 fs/block_dev.c:1808 1 lock held by syz-executor5/9424: #0: 00000000c0095b50 (&bdev->bd_mutex){+.+.}, at: iterate_bdevs+0xce/0x291 fs/block_dev.c:2160 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 878 Comm: khungtaskd Not tainted 4.16.0+ #2 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+0x1b9/0x29f lib/dump_stack.c:53 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x151/0x192 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+0xc10/0xf60 kernel/hung_task.c:249 kthread+0x345/0x410 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54