Buffer I/O error on dev loop0, logical block 3, async page read INFO: task syz-executor2:2885 blocked for more than 120 seconds. Not tainted 4.15.0+ #296 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor2 D23552 2885 4250 0x00000004 Call Trace: context_switch kernel/sched/core.c:2845 [inline] __schedule+0x8eb/0x2060 kernel/sched/core.c:3421 schedule+0xf5/0x430 kernel/sched/core.c:3480 io_schedule+0x1c/0x70 kernel/sched/core.c:5096 wait_on_page_bit_common+0x4b3/0x770 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+0x282/0x430 mm/filemap.c:533 filemap_fdatawait_keep_errors+0x2a/0xb0 mm/filemap.c:600 fdatawait_one_bdev+0x50/0x70 fs/sync.c:95 iterate_bdevs+0x109/0x260 fs/block_dev.c:2147 sys_sync+0x120/0x1c0 fs/sync.c:117 entry_SYSCALL_64_fastpath+0x29/0xa0 RIP: 0033:0x453299 RSP: 002b:00007fad08fafc58 EFLAGS: 00000212 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007fad08fb0700 RCX: 0000000000453299 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000 R13: 0000000000a2f33f R14: 00007fad08fb09c0 R15: 0000000000000000 Showing all locks held in the system: 2 locks held by khungtaskd/757: #0: (rcu_read_lock){....}, at: [<000000001f869407>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<000000001f869407>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<00000000f2438bee>] debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4470 2 locks held by getty/4170: #0: (&tty->ldisc_sem){++++}, at: [<00000000483e3c5d>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000455c08a8>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4171: #0: (&tty->ldisc_sem){++++}, at: [<00000000483e3c5d>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000455c08a8>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4172: #0: (&tty->ldisc_sem){++++}, at: [<00000000483e3c5d>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000455c08a8>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4173: #0: (&tty->ldisc_sem){++++}, at: [<00000000483e3c5d>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000455c08a8>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4174: #0: (&tty->ldisc_sem){++++}, at: [<00000000483e3c5d>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000455c08a8>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4175: #0: (&tty->ldisc_sem){++++}, at: [<00000000483e3c5d>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000455c08a8>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4176: #0: (&tty->ldisc_sem){++++}, at: [<00000000483e3c5d>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000455c08a8>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 3 locks held by kworker/u4:4/7422: #0: ((wq_completion)"writeback"){+.+.}, at: [<00000000b80b8920>] process_one_work+0xaaf/0x1af0 kernel/workqueue.c:2084 #1: ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: [<0000000003b99349>] process_one_work+0xb01/0x1af0 kernel/workqueue.c:2088 #2: (&type->s_umount_key#27){++++}, at: [<00000000996e93b6>] trylock_super+0x20/0x100 fs/super.c:395 1 lock held by blkid/2113: #0: (&bdev->bd_mutex){+.+.}, at: [<000000000a391942>] blkdev_put+0x2a/0x4f0 fs/block_dev.c:1793 1 lock held by syz-executor2/2885: #0: (&bdev->bd_mutex){+.+.}, at: [<000000002148046b>] iterate_bdevs+0xc8/0x260 fs/block_dev.c:2145 1 lock held by syz-executor2/2893: #0: (&bdev->bd_mutex){+.+.}, at: [<000000002148046b>] iterate_bdevs+0xc8/0x260 fs/block_dev.c:2145 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 757 Comm: khungtaskd Not tainted 4.15.0+ #296 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 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.15.0+ #296 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__read_once_size include/linux/compiler.h:183 [inline] RIP: 0010:trace_softirq_raise include/trace/events/irq.h:156 [inline] RIP: 0010:__raise_softirq_irqoff kernel/softirq.c:443 [inline] RIP: 0010:raise_softirq_irqoff+0x23f/0x320 kernel/softirq.c:417 RSP: 0018:ffff8801db407c90 EFLAGS: 00000086 RAX: ffffed003b680f9f RBX: 1ffff1003b680f93 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 1ffff1003b680fc5 RDI: 0000000000000007 RBP: ffff8801db407d60 R08: 1ffff1003b6859ed R09: ffff88021fff8008 R10: ffff88021fff8010 R11: ffff88021fff801d R12: 0000000000000007 R13: ffff8801db407d38 R14: ffff8801db407e68 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8801db400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000001337000 CR3: 0000000006a22005 CR4: 00000000001606f0 Call Trace: scheduler_ipi+0x50b/0x820 kernel/sched/core.c:1802 smp_reschedule_interrupt+0xe6/0x670 arch/x86/kernel/smp.c:277 reschedule_interrupt+0xa9/0xb0 arch/x86/entry/entry_64.S:962 RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54 RSP: 0018:ffffffff86a07c38 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff02 RAX: dffffc0000000000 RBX: 1ffffffff0d40f8a RCX: 0000000000000000 RDX: 1ffffffff0d59280 RSI: 0000000000000001 RDI: ffffffff86ac9400 RBP: ffffffff86a07c38 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff86a07cf0 R14: ffffffff87268d60 R15: 0000000000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:93 [inline] default_idle+0xbf/0x430 arch/x86/kernel/process.c:354 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:345 default_idle_call+0x36/0x90 kernel/sched/idle.c:98 cpuidle_idle_call kernel/sched/idle.c:156 [inline] do_idle+0x24a/0x3b0 kernel/sched/idle.c:246 cpu_startup_entry+0x104/0x120 kernel/sched/idle.c:351 rest_init+0xed/0xf0 init/main.c:436 start_kernel+0x7f1/0x819 init/main.c:716 x86_64_start_reservations+0x2a/0x2c arch/x86/kernel/head64.c:378 x86_64_start_kernel+0x77/0x7a arch/x86/kernel/head64.c:359 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:237 Code: e9 62 fe ff ff 65 ff 05 60 ed be 7e 49 8d 45 c0 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 48 01 d0 c6 00 00 48 8b 15 19 4d e1 05 <49> 89 55 c0 c6 00 f8 e8 85 d9 19 00 85 c0 74 09 80 3d 81 05 e1