Buffer I/O error on dev loop0, logical block 16, async page read INFO: task syz-executor5:24938 blocked for more than 120 seconds. Not tainted 4.15.0+ #286 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor5 D24016 24938 4213 0x00000004 Call Trace: context_switch kernel/sched/core.c:2799 [inline] __schedule+0x8eb/0x2060 kernel/sched/core.c:3375 schedule+0xf5/0x430 kernel/sched/core.c:3434 io_schedule+0x1c/0x70 kernel/sched/core.c:5042 wait_on_page_bit_common+0x4b3/0x770 mm/filemap.c:1100 wait_on_page_bit mm/filemap.c:1133 [inline] wait_on_page_writeback include/linux/pagemap.h:546 [inline] __filemap_fdatawait_range+0x27a/0x420 mm/filemap.c:534 filemap_fdatawait_range mm/filemap.c:559 [inline] filemap_write_and_wait_range+0x74/0xc0 mm/filemap.c:660 generic_file_read_iter+0x409/0x28e0 mm/filemap.c:2335 blkdev_read_iter+0x105/0x170 fs/block_dev.c:1913 call_read_iter include/linux/fs.h:1766 [inline] new_sync_read fs/read_write.c:401 [inline] __vfs_read+0x6a7/0xa00 fs/read_write.c:413 vfs_read+0x11e/0x350 fs/read_write.c:447 SYSC_read fs/read_write.c:573 [inline] SyS_read+0xef/0x220 fs/read_write.c:566 entry_SYSCALL_64_fastpath+0x29/0xa0 RIP: 0033:0x453299 RSP: 002b:00007efdcbef3c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000453299 RDX: 0000000000001000 RSI: 0000000020d8f000 RDI: 0000000000000014 RBP: 00000000000005a5 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f7818 R13: 00000000ffffffff R14: 00007efdcbef46d4 R15: 0000000000000000 Showing all locks held in the system: 2 locks held by khungtaskd/759: #0: (rcu_read_lock){....}, at: [<00000000d9b4b2ca>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<00000000d9b4b2ca>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<00000000e3f911d1>] debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4465 2 locks held by getty/4132: #0: (&tty->ldisc_sem){++++}, at: [<000000007683720d>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000001f7625f0>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4133: #0: (&tty->ldisc_sem){++++}, at: [<000000007683720d>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000001f7625f0>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4134: #0: (&tty->ldisc_sem){++++}, at: [<000000007683720d>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000001f7625f0>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4135: #0: (&tty->ldisc_sem){++++}, at: [<000000007683720d>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000001f7625f0>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4136: #0: (&tty->ldisc_sem){++++}, at: [<000000007683720d>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000001f7625f0>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4137: #0: (&tty->ldisc_sem){++++}, at: [<000000007683720d>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000001f7625f0>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4138: #0: (&tty->ldisc_sem){++++}, at: [<000000007683720d>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000001f7625f0>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 3 locks held by kworker/u4:9/21414: #0: ((wq_completion)"writeback"){+.+.}, at: [<00000000a40bb350>] process_one_work+0xaaf/0x1b10 kernel/workqueue.c:2084 #1: ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: [<00000000c0d32617>] process_one_work+0xb01/0x1b10 kernel/workqueue.c:2088 #2: (&type->s_umount_key#27){.+.+}, at: [<0000000004c6d36a>] trylock_super+0x20/0x100 fs/super.c:395 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 759 Comm: khungtaskd Not tainted 4.15.0+ #286 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+0x194/0x257 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:542 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