syzbot

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BUG: KCSAN: data-race in snd_timer_interrupt / snd_timer_pause

write to 0xffff888121d15610 of 4 bytes by interrupt on cpu 1:
 snd_timer_process_callbacks sound/core/timer.c:793 [inline]
 snd_timer_interrupt+0xa40/0xb50 sound/core/timer.c:919
 snd_hrtimer_callback+0x13a/0x220 sound/core/hrtimer.c:50
 __run_hrtimer+0x154/0x4b0 kernel/time/hrtimer.c:1524
 __hrtimer_run_queues kernel/time/hrtimer.c:1588 [inline]
 hrtimer_interrupt+0x37c/0xa40 kernel/time/hrtimer.c:1650
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline]
 __sysvec_apic_timer_interrupt+0xa3/0x280 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:581
 native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60
 arch_safe_halt arch/x86/include/asm/paravirt.h:150 [inline]
 acpi_safe_halt drivers/acpi/processor_idle.c:111 [inline]
 acpi_idle_do_entry+0x94/0x120 drivers/acpi/processor_idle.c:517
 acpi_idle_enter+0x22e/0x260 drivers/acpi/processor_idle.c:648
 cpuidle_enter_state+0x2ba/0x840 drivers/cpuidle/cpuidle.c:237
 cpuidle_enter+0x3c/0x60 drivers/cpuidle/cpuidle.c:350
 call_cpuidle kernel/sched/idle.c:132 [inline]
 cpuidle_idle_call kernel/sched/idle.c:213 [inline]
 do_idle+0x1e7/0x2c0 kernel/sched/idle.c:273
 cpu_startup_entry+0x15/0x20 kernel/sched/idle.c:369
 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243

read to 0xffff888121d15610 of 4 bytes by task 6833 on cpu 0:
 snd_timer_pause+0x13/0x50 sound/core/timer.c:735
 seq_timer_stop sound/core/seq/seq_timer.c:331 [inline]
 snd_seq_timer_stop+0x8e/0xb0 sound/core/seq/seq_timer.c:341
 snd_seq_queue_process_event sound/core/seq/seq_queue.c:681 [inline]
 snd_seq_control_queue+0x2e5/0x550 sound/core/seq/seq_queue.c:732
 event_input_timer+0x1e/0x30 sound/core/seq/seq_system.c:103
 snd_seq_deliver_single_event+0x31b/0x4f0 sound/core/seq/seq_clientmgr.c:638
 snd_seq_deliver_event+0x192/0x4a0 sound/core/seq/seq_clientmgr.c:839
 snd_seq_kernel_client_dispatch+0x16f/0x190 sound/core/seq/seq_clientmgr.c:2323
 send_timer_event sound/core/seq/oss/seq_oss_timer.c:140 [inline]
 snd_seq_oss_timer_stop sound/core/seq/oss/seq_oss_timer.c:176 [inline]
 snd_seq_oss_timer_ioctl+0x385/0x530 sound/core/seq/oss/seq_oss_timer.c:239
 snd_seq_oss_ioctl+0x5da/0xa50 sound/core/seq/oss/seq_oss_ioctl.c:77
 odev_ioctl+0x47/0x70 sound/core/seq/oss/seq_oss.c:178
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:739
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:739
 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: 0 PID: 6833 Comm: syz-executor.0 Not tainted 5.9.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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