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BUG: KCSAN: data-race in snd_seq_check_queue / snd_seq_control_queue

write to 0xffff88810a057964 of 1 bytes by interrupt on cpu 0:
 snd_seq_check_queue+0x261/0x2a0 sound/core/seq/seq_queue.c:283
 snd_seq_timer_interrupt+0x20e/0x220 sound/core/seq/seq_timer.c:158
 snd_timer_process_callbacks sound/core/timer.c:796 [inline]
 snd_timer_interrupt+0xa1c/0xae0 sound/core/timer.c:919
 snd_hrtimer_callback+0x139/0x200 sound/core/hrtimer.c:50
 __run_hrtimer+0x133/0x420 kernel/time/hrtimer.c:1524
 __hrtimer_run_queues kernel/time/hrtimer.c:1588 [inline]
 hrtimer_interrupt+0x35e/0x9e0 kernel/time/hrtimer.c:1650
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline]
 __sysvec_apic_timer_interrupt+0xa3/0x240 arch/x86/kernel/apic/apic.c:1097
 asm_call_irq_on_stack+0xf/0x20
 __run_sysvec_on_irqstack arch/x86/include/asm/irq_stack.h:37 [inline]
 run_sysvec_on_irqstack_cond arch/x86/include/asm/irq_stack.h:89 [inline]
 sysvec_apic_timer_interrupt+0x80/0xd0 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:631
 arch_local_irq_restore arch/x86/include/asm/paravirt.h:653 [inline]
 kcsan_setup_watchpoint+0x4ee/0x550 kernel/kcsan/core.c:591
 rcu_preempt_read_enter kernel/rcu/tree_plugin.h:354 [inline]
 __rcu_read_lock+0x25/0x40 kernel/rcu/tree_plugin.h:374
 rcu_read_lock include/linux/rcupdate.h:632 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:407 [inline]
 batadv_nc_worker+0x71/0xa10 net/batman-adv/network-coding.c:718
 process_one_work+0x3e1/0x950 kernel/workqueue.c:2272
 worker_thread+0x635/0xb90 kernel/workqueue.c:2418
 kthread+0x1ff/0x220 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

read to 0xffff88810a057964 of 1 bytes by task 20856 on cpu 1:
 queue_access_lock sound/core/seq/seq_queue.c:345 [inline]
 snd_seq_control_queue+0xf4/0x590 sound/core/seq/seq_queue.c:727
 event_input_timer+0x1e/0x30 sound/core/seq/seq_system.c:103
 snd_seq_deliver_single_event+0x2f5/0x4b0 sound/core/seq/seq_clientmgr.c:638
 snd_seq_deliver_event+0x195/0x490 sound/core/seq/seq_clientmgr.c:839
 snd_seq_dispatch_event+0x12e/0x230 sound/core/seq/seq_clientmgr.c:913
 snd_seq_check_queue+0x10e/0x2a0 sound/core/seq/seq_queue.c:264
 snd_seq_enqueue_event+0x24c/0x290 sound/core/seq/seq_queue.c:333
 snd_seq_client_enqueue_event+0x206/0x2a0 sound/core/seq/seq_clientmgr.c:974
 snd_seq_write+0x435/0x550 sound/core/seq/seq_clientmgr.c:1093
 vfs_write+0x1d0/0x6b0 fs/read_write.c:584
 ksys_write+0xce/0x180 fs/read_write.c:639
 __do_sys_write fs/read_write.c:651 [inline]
 __se_sys_write fs/read_write.c:648 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:648
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 20856 Comm: syz-executor.5 Not tainted 5.9.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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