==================================================================
BUG: KCSAN: data-race in snd_seq_check_queue / snd_seq_control_queue

read to 0xffff8880a4bffa24 of 1 bytes by interrupt on cpu 0:
 snd_seq_check_queue+0x59/0x200 sound/core/seq/seq_queue.c:247
 snd_seq_timer_interrupt+0x243/0x280 sound/core/seq/seq_timer.c:158
 snd_timer_process_callbacks+0x1e4/0x220 sound/core/timer.c:750
 snd_timer_interrupt sound/core/timer.c:873 [inline]
 snd_timer_interrupt+0x483/0x930 sound/core/timer.c:794
 snd_hrtimer_callback+0x18f/0x260 sound/core/hrtimer.c:50
 __run_hrtimer kernel/time/hrtimer.c:1517 [inline]
 __hrtimer_run_queues+0x274/0x5f0 kernel/time/hrtimer.c:1579
 hrtimer_interrupt+0x22a/0x480 kernel/time/hrtimer.c:1641
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline]
 smp_apic_timer_interrupt+0xdc/0x280 arch/x86/kernel/apic/apic.c:1135
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 __sanitizer_cov_trace_pc+0x1/0x50 kernel/kcov.c:180
 ipv6_raw_deliver net/ipv6/raw.c:219 [inline]
 raw6_local_deliver+0x268/0x600 net/ipv6/raw.c:235
 ip6_protocol_deliver_rcu+0x27a/0xbe0 net/ipv6/ip6_input.c:382
 ip6_input_finish+0x30/0x50 net/ipv6/ip6_input.c:473
 NF_HOOK include/linux/netfilter.h:307 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ip6_input+0x177/0x190 net/ipv6/ip6_input.c:482
 dst_input include/net/dst.h:442 [inline]
 ip6_rcv_finish+0x110/0x140 net/ipv6/ip6_input.c:76
 NF_HOOK include/linux/netfilter.h:307 [inline]
 NF_HOOK include/linux/netfilter.h:301 [inline]
 ipv6_rcv+0x1a1/0x1b0 net/ipv6/ip6_input.c:306
 __netif_receive_skb_one_core+0xa7/0xe0 net/core/dev.c:5150
 __netif_receive_skb+0x37/0xf0 net/core/dev.c:5264
 process_backlog+0x207/0x4b0 net/core/dev.c:6095
 napi_poll net/core/dev.c:6532 [inline]
 net_rx_action+0x3ae/0xa90 net/core/dev.c:6600
 __do_softirq+0x115/0x33f kernel/softirq.c:292
 do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1082
 do_softirq.part.0+0x6b/0x80 kernel/softirq.c:337
 do_softirq kernel/softirq.c:329 [inline]
 __local_bh_enable_ip+0x76/0x80 kernel/softirq.c:189
 local_bh_enable include/linux/bottom_half.h:32 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:706 [inline]
 ip6_finish_output2+0x730/0xf60 net/ipv6/ip6_output.c:117
 __ip6_finish_output net/ipv6/ip6_output.c:142 [inline]
 __ip6_finish_output+0x2d7/0x330 net/ipv6/ip6_output.c:127
 ip6_finish_output+0x41/0x160 net/ipv6/ip6_output.c:152
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip6_output+0x108/0x290 net/ipv6/ip6_output.c:175
 dst_output include/net/dst.h:436 [inline]
 ip6_local_out+0x74/0x90 net/ipv6/output_core.c:179
 ip6_send_skb+0x53/0x110 net/ipv6/ip6_output.c:1795
 ip6_push_pending_frames+0x9d/0xc0 net/ipv6/ip6_output.c:1815
 rawv6_push_pending_frames net/ipv6/raw.c:613 [inline]
 rawv6_sendmsg+0x1e59/0x2340 net/ipv6/raw.c:956
 inet_sendmsg+0x6d/0x90 net/ipv4/af_inet.c:807
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg+0x9f/0xc0 net/socket.c:659
 ____sys_sendmsg+0x212/0x4d0 net/socket.c:2330
 ___sys_sendmsg+0xb5/0x100 net/socket.c:2384
 __sys_sendmmsg+0x123/0x350 net/socket.c:2474
 __do_sys_sendmmsg net/socket.c:2503 [inline]
 __se_sys_sendmmsg net/socket.c:2500 [inline]
 __x64_sys_sendmmsg+0x64/0x80 net/socket.c:2500
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff8880a4bffa24 of 1 bytes by task 9704 on cpu 1:
 queue_access_unlock sound/core/seq/seq_queue.c:367 [inline]
 snd_seq_control_queue+0x167/0x350 sound/core/seq/seq_queue.c:726
 event_input_timer+0x2f/0x50 sound/core/seq/seq_system.c:103
 snd_seq_deliver_single_event.constprop.0+0x3e8/0x4d0 sound/core/seq/seq_clientmgr.c:638
 snd_seq_deliver_event+0x2e9/0x4c0 sound/core/seq/seq_clientmgr.c:839
 snd_seq_dispatch_event+0xa1/0x340 sound/core/seq/seq_clientmgr.c:913
 snd_seq_check_queue+0xeb/0x200 sound/core/seq/seq_queue.c:262
 snd_seq_enqueue_event+0x163/0x2b0 sound/core/seq/seq_queue.c:330
 snd_seq_client_enqueue_event.constprop.0+0x187/0x2a0 sound/core/seq/seq_clientmgr.c:974
 snd_seq_write+0x23f/0x4d0 sound/core/seq/seq_clientmgr.c:1093
 __vfs_write+0x67/0xc0 fs/read_write.c:494
 vfs_write fs/read_write.c:558 [inline]
 vfs_write+0x18a/0x390 fs/read_write.c:542
 ksys_write+0x17b/0x1b0 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x4c/0x60 fs/read_write.c:620
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 9704 Comm: syz-executor.0 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================