Buffer I/O error on dev loop0, logical block 0, async page read INFO: task syz-executor5:16294 blocked for more than 120 seconds. Not tainted 4.16.0-rc3+ #240 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor5 D23792 16294 4281 0x20020004 Call Trace: context_switch kernel/sched/core.c:2862 [inline] __schedule+0x905/0x2070 kernel/sched/core.c:3440 schedule+0xf5/0x430 kernel/sched/core.c:3499 io_schedule+0x1c/0x70 kernel/sched/core.c:5115 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+0x672/0xba0 mm/filemap.c:1553 grab_cache_page_write_begin+0x6c/0xa0 mm/filemap.c:3088 block_write_begin+0xa6/0x2e0 fs/buffer.c:2086 blkdev_write_begin+0x3c/0x50 fs/block_dev.c:584 generic_perform_write+0x28f/0x600 mm/filemap.c:3138 __generic_file_write_iter+0x366/0x5b0 mm/filemap.c:3263 blkdev_write_iter+0x207/0x3e0 fs/block_dev.c:1893 call_write_iter include/linux/fs.h:1781 [inline] new_sync_write fs/read_write.c:469 [inline] __vfs_write+0x684/0x970 fs/read_write.c:482 vfs_write+0x189/0x510 fs/read_write.c:544 SYSC_write fs/read_write.c:589 [inline] SyS_write+0xef/0x220 fs/read_write.c:581 do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline] do_fast_syscall_32+0x3ec/0xf9f arch/x86/entry/common.c:392 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f32c99 RSP: 002b:00000000f772e09c EFLAGS: 00000286 ORIG_RAX: 0000000000000004 RAX: ffffffffffffffda RBX: 0000000000000013 RCX: 0000000020000000 RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 2 locks held by khungtaskd/799: #0: (rcu_read_lock){....}, at: [<00000000bbbc6f29>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<00000000bbbc6f29>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<00000000a0b99303>] debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4470 1 lock held by rsyslogd/4075: #0: (&f->f_pos_lock){+.+.}, at: [<000000009b8d8d25>] __fdget_pos+0x12b/0x190 fs/file.c:765 2 locks held by getty/4197: #0: (&tty->ldisc_sem){++++}, at: [<0000000025313096>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000a5a8ad2b>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4198: #0: (&tty->ldisc_sem){++++}, at: [<0000000025313096>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000a5a8ad2b>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4199: #0: (&tty->ldisc_sem){++++}, at: [<0000000025313096>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000a5a8ad2b>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4200: #0: (&tty->ldisc_sem){++++}, at: [<0000000025313096>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000a5a8ad2b>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4201: #0: (&tty->ldisc_sem){++++}, at: [<0000000025313096>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000a5a8ad2b>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4202: #0: (&tty->ldisc_sem){++++}, at: [<0000000025313096>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000a5a8ad2b>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4203: #0: (&tty->ldisc_sem){++++}, at: [<0000000025313096>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000a5a8ad2b>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 1 lock held by blkid/16358: #0: (&bdev->bd_mutex){+.+.}, at: [<00000000e1c1dd2e>] __blkdev_put+0xbc/0x7f0 fs/block_dev.c:1757 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 799 Comm: khungtaskd Not tainted 4.16.0-rc3+ #240 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+0x194/0x24d 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+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:407 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