INFO: rcu_sched self-detected stall on CPU 0-....: (124999 ticks this GP) idle=71e/1/4611686018427387906 softirq=223912/223912 fqs=31230 (t=125000 jiffies g=123937 c=123936 q=1051) NMI backtrace for cpu 0 CPU: 0 PID: 18279 Comm: syz-executor6 Not tainted 4.16.0+ #4 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1b9/0x294 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x151/0x192 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+0x175/0x1c2 kernel/rcu/tree.c:1376 print_cpu_stall kernel/rcu/tree.c:1525 [inline] check_cpu_stall.isra.61.cold.80+0x36c/0x59a kernel/rcu/tree.c:1593 __rcu_pending kernel/rcu/tree.c:3356 [inline] rcu_pending kernel/rcu/tree.c:3401 [inline] rcu_check_callbacks+0x21b/0xad0 kernel/rcu/tree.c:2763 update_process_times+0x2d/0x70 kernel/time/timer.c:1636 tick_sched_handle+0xa0/0x180 kernel/time/tick-sched.c:171 tick_sched_timer+0x42/0x130 kernel/time/tick-sched.c:1179 __run_hrtimer kernel/time/hrtimer.c:1337 [inline] __hrtimer_run_queues+0x3e3/0x10a0 kernel/time/hrtimer.c:1399 hrtimer_interrupt+0x286/0x650 kernel/time/hrtimer.c:1457 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1025 [inline] smp_apic_timer_interrupt+0x15d/0x710 arch/x86/kernel/apic/apic.c:1050 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:862 RIP: 0010:__sanitizer_cov_trace_const_cmp4+0xa/0x20 kernel/kcov.c:188 RSP: 0018:ffff88018e4dee18 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000000 RBX: 0000000000000004 RCX: dffffc0000000000 RDX: 0000000000000004 RSI: 0000000000000002 RDI: 0000000000000005 RBP: ffff88018e4dee70 R08: ffff8801c2e88280 R09: 0000000000000006 R10: ffff8801c2e88280 R11: 0000000000000000 R12: 0000000000000001 R13: ffff8801ceadb200 R14: ffff8801bbba6600 R15: ffffffffffffffe0 snd_pcm_oss_write2+0x34c/0x460 sound/core/oss/pcm_oss.c:1373 snd_pcm_oss_sync1+0x332/0x5a0 sound/core/oss/pcm_oss.c:1606 snd_pcm_oss_sync.isra.29+0x790/0x980 sound/core/oss/pcm_oss.c:1682 snd_pcm_oss_release+0x214/0x290 sound/core/oss/pcm_oss.c:2559 __fput+0x34d/0x890 fs/file_table.c:209 ____fput+0x15/0x20 fs/file_table.c:243 task_work_run+0x1e4/0x290 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x1aee/0x2730 kernel/exit.c:865 do_group_exit+0x16f/0x430 kernel/exit.c:968 get_signal+0x886/0x1960 kernel/signal.c:2469 do_signal+0x98/0x2040 arch/x86/kernel/signal.c:810 exit_to_usermode_loop+0x28a/0x310 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_64+0x792/0x9d0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x455259 RSP: 002b:00007f23fa25fce8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: 0000000000000000 RBX: 000000000072bec8 RCX: 0000000000455259 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000072bec8 RBP: 000000000072bec8 R08: 0000000000000000 R09: 000000000072bea0 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000a3e81f R14: 00007f23fa2609c0 R15: 0000000000000000 INFO: task kworker/1:2:2081 blocked for more than 120 seconds. Not tainted 4.16.0+ #4 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/1:2 D19256 2081 2 0x80000000 Workqueue: events xfrm_state_gc_task Call Trace: context_switch kernel/sched/core.c:2848 [inline] __schedule+0x807/0x1e40 kernel/sched/core.c:3490 schedule+0xef/0x430 kernel/sched/core.c:3549 schedule_timeout+0x1b5/0x240 kernel/time/timer.c:1777 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x3e7/0x870 kernel/sched/completion.c:136 __wait_rcu_gp+0x257/0x350 kernel/rcu/update.c:414 synchronize_sched.part.64+0xe3/0xf0 kernel/rcu/tree.c:3209 synchronize_sched+0x76/0xf0 kernel/rcu/tree.c:3210 synchronize_rcu include/linux/rcupdate.h:94 [inline] xfrm_state_gc_task+0xef/0x6f0 net/xfrm/xfrm_state.c:467 process_one_work+0xc1e/0x1b50 kernel/workqueue.c:2145 worker_thread+0x1cc/0x1440 kernel/workqueue.c:2279 kthread+0x345/0x410 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411 Showing all locks held in the system: 2 locks held by khungtaskd/881: #0: 0000000007d1bb2b (rcu_read_lock){....}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: 0000000007d1bb2b (rcu_read_lock){....}, at: watchdog+0x1ff/0xf60 kernel/hung_task.c:249 #1: 00000000bb3a1f4f (tasklist_lock){.+.+}, at: debug_show_all_locks+0xde/0x34a kernel/locking/lockdep.c:4470 2 locks held by kworker/1:2/2081: #0: 00000000105980c0 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline] #0: 00000000105980c0 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000105980c0 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000105980c0 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:57 [inline] #0: 00000000105980c0 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000105980c0 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000105980c0 ((wq_completion)"events"){+.+.}, at: process_one_work+0xaef/0x1b50 kernel/workqueue.c:2116 #1: 000000004082c54c (xfrm_state_gc_work){+.+.}, at: process_one_work+0xb46/0x1b50 kernel/workqueue.c:2120 2 locks held by getty/4444: #0: 000000002beaf250 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000c0ed9172 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4445: #0: 00000000b10349a0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000250c92b5 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4446: #0: 0000000010f82d16 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000a53a3a2b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4447: #0: 0000000044aa1657 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000007baa1636 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4448: #0: 00000000f438abd7 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000a16aeabc (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4449: #0: 0000000018f4fad5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000008272ffae (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 2 locks held by getty/4450: #0: 0000000018f2daee (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000060538011 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 881 Comm: khungtaskd Not tainted 4.16.0+ #4 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1b9/0x294 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x151/0x192 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+0xc10/0xf60 kernel/hung_task.c:249 kthread+0x345/0x410 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 18279 Comm: syz-executor6 Not tainted 4.16.0+ #4 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:hlock_class kernel/locking/lockdep.c:152 [inline] RIP: 0010:mark_lock+0xe0/0x19e0 kernel/locking/lockdep.c:3121 RSP: 0018:ffff88018e4de998 EFLAGS: 00000046 RAX: 0000000000000470 RBX: 1ffff10031c9bd38 RCX: 1ffff100385d1163 RDX: 0000000000000000 RSI: ffff8801c2e88af8 RDI: ffff8801c2e88280 RBP: ffff88018e4deac8 R08: 0000000000000002 R09: 0000000000000002 R10: ffff8801c2e88280 R11: 0000000000000000 R12: ffff8801c2e88af8 R13: ffff8801c2e88b18 R14: 0000000000000003 R15: 0000000000000004 FS: 00007f23fa260700(0000) GS:ffff8801db000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f82bc893140 CR3: 0000000008a6a000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: mark_held_locks+0xc9/0x160 kernel/locking/lockdep.c:2807 __trace_hardirqs_on_caller kernel/locking/lockdep.c:2828 [inline] trace_hardirqs_on_caller+0x19e/0x5c0 kernel/locking/lockdep.c:2883 trace_hardirqs_on+0xd/0x10 kernel/locking/lockdep.c:2890 snd_pcm_stream_unlock_irq+0x83/0xf0 sound/core/pcm_native.c:166 __snd_pcm_lib_xfer+0x739/0x1d10 sound/core/pcm_lib.c:2246 snd_pcm_oss_write3+0xe9/0x220 sound/core/oss/pcm_oss.c:1236 snd_pcm_oss_write2+0x34c/0x460 sound/core/oss/pcm_oss.c:1373 snd_pcm_oss_sync1+0x332/0x5a0 sound/core/oss/pcm_oss.c:1606 snd_pcm_oss_sync.isra.29+0x790/0x980 sound/core/oss/pcm_oss.c:1682 snd_pcm_oss_release+0x214/0x290 sound/core/oss/pcm_oss.c:2559 __fput+0x34d/0x890 fs/file_table.c:209 ____fput+0x15/0x20 fs/file_table.c:243 task_work_run+0x1e4/0x290 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x1aee/0x2730 kernel/exit.c:865 do_group_exit+0x16f/0x430 kernel/exit.c:968 get_signal+0x886/0x1960 kernel/signal.c:2469 do_signal+0x98/0x2040 arch/x86/kernel/signal.c:810 exit_to_usermode_loop+0x28a/0x310 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_64+0x792/0x9d0 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x455259 RSP: 002b:00007f23fa25fce8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: 0000000000000000 RBX: 000000000072bec8 RCX: 0000000000455259 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000072bec8 RBP: 000000000072bec8 R08: 0000000000000000 R09: 000000000072bea0 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000a3e81f R14: 00007f23fa2609c0 R15: 0000000000000000 Code: a9 ff 1f 0f 84 b0 00 00 00 48 ba 00 00 00 00 00 fc ff df 4c 89 e9 48 c1 e9 03 0f b6 14 11 84 d2 74 09 80 fa 03 0f 8e 58 06 00 00 <25> ff 1f 00 00 48 8d 14 80 4c 8d 34 90 49 c1 e6 04 49 81 ee 50 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.287 msecs