Buffer I/O error on dev loop0, logical block 1, async page read kworker/dying (32) used greatest stack depth: 8408 bytes left Buffer I/O error on dev loop0, logical block 3, async page read INFO: task syz-executor1:13153 blocked for more than 120 seconds. Not tainted 4.16.0+ #380 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor1 D23376 13153 4488 0x00000004 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 io_schedule+0x1c/0x70 kernel/sched/core.c:5169 wait_on_page_bit_common mm/filemap.c:1099 [inline] __lock_page+0x574/0x720 mm/filemap.c:1272 lock_page include/linux/pagemap.h:483 [inline] pagecache_get_page+0x69c/0xbf0 mm/filemap.c:1553 grab_cache_page_write_begin+0x6c/0xa0 mm/filemap.c:3088 block_write_begin+0xa6/0x310 fs/buffer.c:2086 blkdev_write_begin+0x3c/0x50 fs/block_dev.c:584 generic_perform_write+0x28f/0x610 mm/filemap.c:3138 __generic_file_write_iter+0x366/0x5b0 mm/filemap.c:3263 blkdev_write_iter+0x207/0x3e0 fs/block_dev.c:1908 call_write_iter include/linux/fs.h:1782 [inline] do_iter_readv_writev+0x55c/0x830 fs/read_write.c:680 do_iter_write+0x154/0x540 fs/read_write.c:959 vfs_writev+0x18a/0x340 fs/read_write.c:1004 do_writev+0xfc/0x2a0 fs/read_write.c:1039 SYSC_writev fs/read_write.c:1112 [inline] SyS_writev+0x27/0x30 fs/read_write.c:1109 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x4552d9 RSP: 002b:00007ff0cf403c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 00007ff0cf4046d4 RCX: 00000000004552d9 RDX: 0000000000000003 RSI: 0000000020000b80 RDI: 0000000000000016 RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000006c7 R14: 00000000006fd348 R15: 0000000000000000 Showing all locks held in the system: 2 locks held by khungtaskd/878: #0: 00000000b88da9ed (rcu_read_lock){....}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: 00000000b88da9ed (rcu_read_lock){....}, at: watchdog+0x1d6/0xd70 kernel/hung_task.c:249 #1: 00000000065e810a (tasklist_lock){.+.+}, at: debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4470 2 locks held by login/4409: #0: 0000000047d903dd (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000c53c7c80 (&tty->atomic_write_lock){+.+.}, at: tty_write_lock+0x21/0x60 drivers/tty/tty_io.c:884 2 locks held by getty/4410: #0: 000000004a0717d1 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000004f839c1d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4411: #0: 00000000bad6e329 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000005d9d839 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4412: #0: 0000000084138743 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000037367791 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4413: #0: 000000009803935c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000c4ceb578 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4414: #0: 00000000f2f6684d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000dd3bd32a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4415: #0: 000000006b6b7157 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000147d2044 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 3 locks held by kworker/u4:6/14167: #0: 000000003cabef85 ((wq_completion)"writeback"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline] #0: 000000003cabef85 ((wq_completion)"writeback"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 000000003cabef85 ((wq_completion)"writeback"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 000000003cabef85 ((wq_completion)"writeback"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:57 [inline] #0: 000000003cabef85 ((wq_completion)"writeback"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 000000003cabef85 ((wq_completion)"writeback"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 000000003cabef85 ((wq_completion)"writeback"){+.+.}, at: process_one_work+0xb83/0x1c40 kernel/workqueue.c:2116 #1: 00000000cb8f8230 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0xbd9/0x1c40 kernel/workqueue.c:2120 #2: 00000000df7b53ce (&type->s_umount_key#35){++++}, at: trylock_super+0x20/0x100 fs/super.c:395 1 lock held by blkid/10797: #0: 0000000045acf617 (&bdev->bd_mutex){+.+.}, at: blkdev_put+0x2a/0x4f0 fs/block_dev.c:1808 1 lock held by syz-executor1/13167: #0: 0000000045acf617 (&bdev->bd_mutex){+.+.}, at: iterate_bdevs+0xc8/0x260 fs/block_dev.c:2160 1 lock held by syz-executor1/13174: #0: 0000000045acf617 (&bdev->bd_mutex){+.+.}, at: iterate_bdevs+0xc8/0x260 fs/block_dev.c:2160 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 878 Comm: khungtaskd Not tainted 4.16.0+ #380 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