Buffer I/O error on dev loop0, logical block 0, async page read BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 124s! BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=-20 stuck for 123s! Showing busy workqueues and worker pools: workqueue events: flags=0x0 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=8/256 pending: defense_work_handler, defense_work_handler, defense_work_handler, defense_work_handler, defense_work_handler, defense_work_handler, defense_work_handler, cache_reap workqueue events_power_efficient: flags=0x80 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 pending: neigh_periodic_work workqueue mm_percpu_wq: flags=0x8 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 pending: vmstat_update workqueue kblockd: flags=0x18 pwq 3: cpus=1 node=0 flags=0x0 nice=-20 active=1/256 pending: blk_timeout_work workqueue dm_bufio_cache: flags=0x8 pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 pending: work_fn INFO: task syz-executor3:8539 blocked for more than 120 seconds. Not tainted 4.16.0-rc7+ #278 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor3 D20880 8539 4478 0xa0020002 Call Trace: context_switch kernel/sched/core.c:2862 [inline] __schedule+0x8fb/0x1ec0 kernel/sched/core.c:3440 schedule+0xf5/0x430 kernel/sched/core.c:3499 schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3557 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0xaad/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 perf_trace_destroy+0x28/0x100 kernel/trace/trace_event_perf.c:234 INFO: rcu_sched self-detected stall on CPU tp_perf_event_destroy+0x15/0x20 kernel/events/core.c:7976 1-....: (124999 ticks this GP) idle=442/1/4611686018427387906 softirq=117780/117780 fqs=31148 _free_event+0x3bd/0x10f0 kernel/events/core.c:4121 (t=125000 jiffies g=58697 c=58696 q=402) NMI backtrace for cpu 1 CPU: 1 PID: 8546 Comm: syz-executor1 Not tainted 4.16.0-rc7+ #278 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+0x123/0x180 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_single_cpu_backtrace include/linux/nmi.h:156 [inline] rcu_dump_cpu_stacks+0x186/0x1de kernel/rcu/tree.c:1375 print_cpu_stall kernel/rcu/tree.c:1524 [inline] check_cpu_stall.isra.61+0xbb8/0x15b0 kernel/rcu/tree.c:1592 put_event+0x24/0x30 kernel/events/core.c:4204 perf_event_release_kernel+0x6e8/0xfc0 kernel/events/core.c:4310 __rcu_pending kernel/rcu/tree.c:3361 [inline] rcu_pending kernel/rcu/tree.c:3423 [inline] rcu_check_callbacks+0x238/0xd20 kernel/rcu/tree.c:2763 perf_release+0x37/0x50 kernel/events/core.c:4320 update_process_times+0x30/0x60 kernel/time/timer.c:1636 __fput+0x327/0x7e0 fs/file_table.c:209 tick_sched_handle+0x85/0x160 kernel/time/tick-sched.c:162 tick_sched_timer+0x42/0x120 kernel/time/tick-sched.c:1194 __run_hrtimer kernel/time/hrtimer.c:1349 [inline] __hrtimer_run_queues+0x39c/0xec0 kernel/time/hrtimer.c:1411 ____fput+0x15/0x20 fs/file_table.c:243 task_work_run+0x199/0x270 kernel/task_work.c:113 hrtimer_interrupt+0x2a5/0x6f0 kernel/time/hrtimer.c:1469 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1025 [inline] smp_apic_timer_interrupt+0x14a/0x700 arch/x86/kernel/apic/apic.c:1050 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x9bb/0x1ad0 kernel/exit.c:865 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:857 RIP: 0010:check_kcov_mode kernel/kcov.c:67 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x20/0x50 kernel/kcov.c:101 RSP: 0018:ffff8801c4b97bc8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff12 RAX: ffff8801a0d666c0 RBX: dffffc0000000000 RCX: ffffffff83fb9ea1 RDX: 0000000000000000 RSI: ffffc90008e12000 RDI: ffff8801d28a6fb8 RBP: ffff8801c4b97bc8 R08: 0000000000000000 R09: 1ffff10038972f2c R10: ffff8801c4b97928 R11: 0000000000000001 R12: ffff88019d45f818 R13: ffff8801d3fb5b00 R14: ffff8801bfd56040 R15: ffff8801d3fb5c50 is_loop_device drivers/block/loop.c:691 [inline] loop_set_fd drivers/block/loop.c:879 [inline] lo_ioctl+0x561/0x1b70 drivers/block/loop.c:1358 lo_compat_ioctl+0xab/0x140 drivers/block/loop.c:1556 compat_blkdev_ioctl+0x3ae/0x1840 block/compat_ioctl.c:406 C_SYSC_ioctl fs/compat_ioctl.c:1461 [inline] compat_SyS_ioctl+0x151/0x2a30 fs/compat_ioctl.c:1407 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: 0023:0xf7facc99 RSP: 002b:00000000f77a809c EFLAGS: 00000286 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000015 RCX: 0000000000004c00 RDX: 0000000000000013 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 do_group_exit+0x149/0x400 kernel/exit.c:968 get_signal+0x73a/0x16d0 kernel/signal.c:2469 do_signal+0x90/0x1e90 arch/x86/kernel/signal.c:809 exit_to_usermode_loop+0x258/0x2f0 arch/x86/entry/common.c:162 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline] syscall_return_slowpath arch/x86/entry/common.c:265 [inline] do_syscall_32_irqs_on arch/x86/entry/common.c:336 [inline] do_fast_syscall_32+0xbe6/0xf9f arch/x86/entry/common.c:392 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f94c99 RSP: 002b:00000000f776f10c EFLAGS: 00000296 ORIG_RAX: 00000000000000f0 RAX: fffffffffffffe00 RBX: 000000000813af98 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 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/868: #0: (rcu_read_lock){....}, at: [<00000000905dbed8>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<00000000905dbed8>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<00000000d482a779>] debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4470 2 locks held by getty/4396: #0: (&tty->ldisc_sem){++++}, at: [<000000000e5b71c1>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000ac27cbf0>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4397: #0: (&tty->ldisc_sem){++++}, at: [<000000000e5b71c1>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000ac27cbf0>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4398: #0: (&tty->ldisc_sem){++++}, at: [<000000000e5b71c1>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000ac27cbf0>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4399: #0: (&tty->ldisc_sem){++++}, at: [<000000000e5b71c1>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000ac27cbf0>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4400: #0: (&tty->ldisc_sem){++++}, at: [<000000000e5b71c1>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000ac27cbf0>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4401: #0: (&tty->ldisc_sem){++++}, at: [<000000000e5b71c1>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000ac27cbf0>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4402: #0: (&tty->ldisc_sem){++++}, at: [<000000000e5b71c1>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000ac27cbf0>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 1 lock held by syz-executor3/8539: #0: (event_mutex){+.+.}, at: [<0000000017ea9990>] perf_trace_destroy+0x28/0x100 kernel/trace/trace_event_perf.c:234 1 lock held by syz-executor1/8557: #0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<000000004810e116>] lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1355 1 lock held by syz-executor4/8536: #0: (event_mutex){+.+.}, at: [<0000000017ea9990>] perf_trace_destroy+0x28/0x100 kernel/trace/trace_event_perf.c:234 3 locks held by syz-executor7/8545: #0: (&sig->cred_guard_mutex){+.+.}, at: [<00000000decdf1ce>] SYSC_perf_event_open+0x12ca/0x2e00 kernel/events/core.c:9990 #1: (&pmus_srcu){....}, at: [<00000000d2f6e133>] perf_event_alloc+0xf55/0x2b00 kernel/events/core.c:9551 #2: (event_mutex){+.+.}, at: [<000000000e39911b>] perf_trace_init+0x58/0xab0 kernel/trace/trace_event_perf.c:216 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 868 Comm: khungtaskd Not tainted 4.16.0-rc7+ #278 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+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+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:406 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 8546 Comm: syz-executor1 Not tainted 4.16.0-rc7+ #278 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__read_once_size include/linux/compiler.h:188 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:69 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x26/0x50 kernel/kcov.c:101 RSP: 0018:ffff8801c4b97bc8 EFLAGS: 00000246 RAX: ffff8801a0d666c0 RBX: dffffc0000000000 RCX: ffffffff83fb9edc RDX: 0000000000000002 RSI: ffffc90008e12000 RDI: ffff88019d45f864 RBP: ffff8801c4b97bc8 R08: 0000000000000000 R09: 1ffff10038972f2c R10: ffff8801c4b97928 R11: 0000000000000001 R12: ffff88019d45f818 R13: ffff8801d3fb5b00 R14: ffff8801bfd56040 R15: ffff8801d3fb5c50 FS: 0000000000000000(0000) GS:ffff8801db300000(0063) knlGS:00000000f77a8b40 CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 CR2: 000000009bc21000 CR3: 00000001b83f4004 CR4: 00000000001626e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: loop_set_fd drivers/block/loop.c:882 [inline] lo_ioctl+0x59c/0x1b70 drivers/block/loop.c:1358 lo_compat_ioctl+0xab/0x140 drivers/block/loop.c:1556 compat_blkdev_ioctl+0x3ae/0x1840 block/compat_ioctl.c:406 C_SYSC_ioctl fs/compat_ioctl.c:1461 [inline] compat_SyS_ioctl+0x151/0x2a30 fs/compat_ioctl.c:1407 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: 0023:0xf7facc99 RSP: 002b:00000000f77a809c EFLAGS: 00000286 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000015 RCX: 0000000000004c00 RDX: 0000000000000013 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Code: 90 90 90 90 90 55 65 48 8b 04 25 c0 ed 01 00 48 89 e5 65 8b 15 1c 24 90 7e 81 e2 00 01 1f 00 48 8b 4d 08 75 2b 8b 90 b8 12 00 00 <83> fa 02 75 20 48 8b b0 c0 12 00 00 8b 80 bc 12 00 00 48 8b 16