Buffer I/O error on dev loop1, logical block 1440, async page read INFO: task syz-executor5:27466 blocked for more than 120 seconds. Not tainted 4.9.94-g8683408 #4 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor5 D26872 27466 3869 0x20020004 ffff8801a64c8000 ffff8801b77af480 ffff8801b77af480 ffff8801cb21e000 ffff8801db321b98 ffff8801cb6d6fa0 ffffffff839e140d 1ffff100396dade8 ffffffff85341f38 0000000041b58ab3 00ffffff841c03b8 ffff8801db322468 Call Trace: [] schedule+0x7f/0x1b0 kernel/sched/core.c:3557 [] schedule_timeout+0x861/0xf70 kernel/time/timer.c:1768 [] io_schedule_timeout+0x1ba/0x390 kernel/sched/core.c:5180 [] io_schedule include/linux/sched.h:460 [inline] [] bit_wait_io+0x19/0xa0 kernel/sched/wait.c:582 [] __wait_on_bit_lock+0xce/0x1c0 kernel/sched/wait.c:421 [] __lock_page+0xff/0x160 mm/filemap.c:934 [] lock_page include/linux/pagemap.h:454 [inline] [] write_cache_pages+0x638/0xef0 mm/page-writeback.c:2214 [] generic_writepages+0xda/0x150 mm/page-writeback.c:2333 [] blkdev_writepages+0x1d/0x30 fs/block_dev.c:1764 [] do_writepages+0xef/0x1d0 mm/page-writeback.c:2347 [] __filemap_fdatawrite_range+0x1b3/0x250 mm/filemap.c:390 [] filemap_write_and_wait_range+0x59/0xb0 mm/filemap.c:580 [] blkdev_fsync+0x66/0xb0 fs/block_dev.c:369 [] vfs_fsync_range+0x10c/0x260 fs/sync.c:195 [] generic_write_sync include/linux/fs.h:2607 [inline] [] blkdev_write_iter+0x2a9/0x370 fs/block_dev.c:1720 [] vfs_iter_write+0x2e0/0x460 fs/read_write.c:390 [] iter_file_splice_write+0x5fb/0xb30 fs/splice.c:768 [] do_splice_from fs/splice.c:870 [inline] [] direct_splice_actor+0x128/0x190 fs/splice.c:1037 [] splice_direct_to_actor+0x2c1/0x7e0 fs/splice.c:992 [] do_splice_direct+0x1a3/0x270 fs/splice.c:1080 [] do_sendfile+0x4f0/0xc60 fs/read_write.c:1393 [] C_SYSC_sendfile fs/read_write.c:1469 [inline] [] compat_SyS_sendfile+0xd1/0x160 fs/read_write.c:1458 [] do_syscall_32_irqs_on arch/x86/entry/common.c:325 [inline] [] do_fast_syscall_32+0x2f7/0x870 arch/x86/entry/common.c:387 [] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137 Showing all locks held in the system: 2 locks held by khungtaskd/518: #0: (rcu_read_lock){......}, at: [] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline] #0: (rcu_read_lock){......}, at: [] watchdog+0x11c/0xa20 kernel/hung_task.c:239 #1: (tasklist_lock){.+.+..}, at: [] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336 1 lock held by rsyslogd/3681: #0: (&f->f_pos_lock){+.+.+.}, at: [] __fdget_pos+0xac/0xd0 fs/file.c:781 2 locks held by getty/3778: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.+.}, at: [] n_tty_read+0x202/0x16b0 drivers/tty/n_tty.c:2133 3 locks held by kworker/u4:0/4502: #0: ("writeback"){++++.+}, at: [] work_static include/linux/workqueue.h:186 [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+0x6ee/0x1500 kernel/workqueue.c:2085 #1: ((&(&wb->dwork)->work)){+.+.+.}, at: [] process_one_work+0x728/0x1500 kernel/workqueue.c:2089 #2: (&type->s_umount_key#29){++++..}, at: [] trylock_super+0x20/0xf0 fs/super.c:393 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 518 Comm: khungtaskd Not tainted 4.9.94-g8683408 #4 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ffff8801d876fd08 ffffffff81eb0aa9 0000000000000000 0000000000000001 0000000000000001 0000000000000001 ffffffff810b7d60 ffff8801d876fd40 ffffffff81ebbdd7 0000000000000001 0000000000000000 0000000000000002 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99 [] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60 [] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [] check_hung_task kernel/hung_task.c:125 [inline] [] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline] [] watchdog+0x6b4/0xa20 kernel/hung_task.c:239 [] kthread+0x26d/0x300 kernel/kthread.c:211 [] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff839f0f16