rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-....: (10499 ticks this GP) idle=5e6/1/0x4000000000000002 softirq=133402/133402 fqs=5242 rcu: (t=10500 jiffies g=183485 q=1545) NMI backtrace for cpu 0 CPU: 0 PID: 29318 Comm: syz-executor.3 Not tainted 5.1.0-rc6+ #84 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+0x172/0x1f0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1be/0x236 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:164 [inline] rcu_dump_cpu_stacks+0x183/0x1cf kernel/rcu/tree.c:1223 print_cpu_stall kernel/rcu/tree.c:1360 [inline] check_cpu_stall kernel/rcu/tree.c:1434 [inline] rcu_pending kernel/rcu/tree.c:3103 [inline] rcu_sched_clock_irq.cold+0x500/0xa4a kernel/rcu/tree.c:2544 update_process_times+0x32/0x80 kernel/time/timer.c:1635 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:161 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1271 __run_hrtimer kernel/time/hrtimer.c:1389 [inline] __hrtimer_run_queues+0x33e/0xde0 kernel/time/hrtimer.c:1451 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1035 [inline] smp_apic_timer_interrupt+0x120/0x570 arch/x86/kernel/apic/apic.c:1060 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:767 [inline] RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x95/0xe0 kernel/locking/spinlock.c:184 Code: 48 c7 c0 70 97 92 88 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 39 48 83 3d 52 d4 81 01 00 74 24 48 89 df 57 9d <0f> 1f 44 00 00 bf 01 00 00 00 e8 bc 15 3d fa 65 8b 05 55 2a f1 78 RSP: 0018:ffff88803f5a7810 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13 RAX: 1ffffffff11252ee RBX: 0000000000000286 RCX: 1ffff110132fe914 RDX: dffffc0000000000 RSI: ffff8880997f4880 RDI: 0000000000000286 RBP: ffff88803f5a7820 R08: ffff8880997f4000 R09: ffff8880997f48a0 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff892b5060 R13: ffff88809b5ff840 R14: 0000000000000286 R15: ffffffff8b1243a0 spin_unlock_irqrestore include/linux/spinlock.h:384 [inline] snd_seq_client_use_ptr+0xa1/0x3f0 sound/core/seq/seq_clientmgr.c:178 get_event_dest_client sound/core/seq/seq_clientmgr.c:487 [inline] snd_seq_deliver_single_event.constprop.0+0xf5/0x870 sound/core/seq/seq_clientmgr.c:595 snd_seq_deliver_event+0x57f/0x8e0 sound/core/seq/seq_clientmgr.c:822 snd_seq_dispatch_event+0x131/0x5c0 sound/core/seq/seq_clientmgr.c:896 snd_seq_check_queue.part.0+0x139/0x360 sound/core/seq/seq_queue.c:275 snd_seq_check_queue sound/core/seq/seq_queue.c:255 [inline] snd_seq_enqueue_event+0x1fb/0x4d0 sound/core/seq/seq_queue.c:343 snd_seq_client_enqueue_event+0x287/0x4c0 sound/core/seq/seq_clientmgr.c:957 snd_seq_write+0x3cc/0x6e0 sound/core/seq/seq_clientmgr.c:1074 __vfs_write+0x8d/0x110 fs/read_write.c:485 vfs_write+0x20c/0x580 fs/read_write.c:549 ksys_write+0x14f/0x2d0 fs/read_write.c:599 __do_sys_write fs/read_write.c:611 [inline] __se_sys_write fs/read_write.c:608 [inline] __x64_sys_write+0x73/0xb0 fs/read_write.c:608 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x458d99 Code: ad b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fc844699c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000458d99 RDX: 00000000ffffff76 RSI: 0000000020000000 RDI: 0000000000000006 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc84469a6d4 R13: 00000000004c892d R14: 00000000004df108 R15: 00000000ffffffff