rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (10499 ticks this GP) idle=3b7/1/0x4000000000000000 softirq=94047/94047 fqs=5106 
	(t=10500 jiffies g=170673 q=1175)
NMI backtrace for cpu 0
CPU: 0 PID: 8024 Comm: syz-executor.4 Not tainted 5.15.0-rc2-next-20210924-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0x1ae/0x220 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:343
 print_cpu_stall kernel/rcu/tree_stall.h:627 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:711 [inline]
 rcu_pending kernel/rcu/tree.c:3878 [inline]
 rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2597
 update_process_times+0x16d/0x200 kernel/time/timer.c:1785
 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226
 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1428
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline]
 __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103
 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:__sanitizer_cov_trace_cmp4+0xc/0x70 kernel/kcov.c:257
Code: 00 00 00 48 89 7c 30 e8 48 89 4c 30 f0 4c 89 54 d8 20 48 89 10 5b c3 0f 1f 80 00 00 00 00 41 89 f8 bf 03 00 00 00 4c 8b 14 24 <89> f1 65 48 8b 34 25 40 70 02 00 e8 64 ef ff ff 84 c0 74 4b 48 8b
RSP: 0018:ffffc90002f3f868 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc900145bc000
RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000003
RBP: dffffc0000000000 R08: 0000000000000000 R09: ffff888147ff3093
R10: ffffffff86f2b987 R11: 0000000000000000 R12: ffff888147ff3800
R13: ffff888147ff3080 R14: ffff888147ff3090 R15: 0000000000000000
 snd_seq_port_use_ptr+0xd7/0x1a0 sound/core/seq/seq_ports.c:53
 snd_seq_deliver_single_event.constprop.0+0x1ba/0x820 sound/core/seq/seq_clientmgr.c:617
 snd_seq_deliver_event+0x4e7/0x970 sound/core/seq/seq_clientmgr.c:841
 snd_seq_dispatch_event+0x112/0x580 sound/core/seq/seq_clientmgr.c:915
 snd_seq_check_queue+0x18a/0x3f0 sound/core/seq/seq_queue.c:265
 snd_seq_enqueue_event+0x1ed/0x3e0 sound/core/seq/seq_queue.c:334
 snd_seq_client_enqueue_event.constprop.0+0x230/0x440 sound/core/seq/seq_clientmgr.c:976
 snd_seq_write+0x388/0x690 sound/core/seq/seq_clientmgr.c:1096
 vfs_write+0x28e/0xae0 fs/read_write.c:592
 ksys_write+0x1ee/0x250 fs/read_write.c:647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f8216604709
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8213b7b188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f8216708f60 RCX: 00007f8216604709
RDX: 00000000fffffee4 RSI: 00000000200000c0 RDI: 0000000000000005
RBP: 00007f821665ecb4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffca3cfd09f R14: 00007f8213b7b300 R15: 0000000000022000
 </TASK>
----------------
Code disassembly (best guess):
   0:	00 00                	add    %al,(%rax)
   2:	00 48 89             	add    %cl,-0x77(%rax)
   5:	7c 30                	jl     0x37
   7:	e8 48 89 4c 30       	callq  0x304c8954
   c:	f0 4c 89 54 d8 20    	lock mov %r10,0x20(%rax,%rbx,8)
  12:	48 89 10             	mov    %rdx,(%rax)
  15:	5b                   	pop    %rbx
  16:	c3                   	retq
  17:	0f 1f 80 00 00 00 00 	nopl   0x0(%rax)
  1e:	41 89 f8             	mov    %edi,%r8d
  21:	bf 03 00 00 00       	mov    $0x3,%edi
  26:	4c 8b 14 24          	mov    (%rsp),%r10
* 2a:	89 f1                	mov    %esi,%ecx <-- trapping instruction
  2c:	65 48 8b 34 25 40 70 	mov    %gs:0x27040,%rsi
  33:	02 00
  35:	e8 64 ef ff ff       	callq  0xffffef9e
  3a:	84 c0                	test   %al,%al
  3c:	74 4b                	je     0x89
  3e:	48                   	rex.W
  3f:	8b                   	.byte 0x8b