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BUG: KCSAN: data-race in expire_timers / try_to_del_timer_sync

write to 0xffff888237d376c8 of 8 bytes by interrupt on cpu 1:
 expire_timers+0x13d/0x250 kernel/time/timer.c:1465
 __run_timers+0x358/0x420 kernel/time/timer.c:1732
 run_timer_softirq+0x19/0x30 kernel/time/timer.c:1745
 __do_softirq+0x12c/0x26e kernel/softirq.c:558
 invoke_softirq kernel/softirq.c:432 [inline]
 __irq_exit_rcu+0x9a/0xb0 kernel/softirq.c:636
 sysvec_apic_timer_interrupt+0x69/0x80 arch/x86/kernel/apic/apic.c:1100
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
 dd_insert_request+0x29f/0x4c0 block/mq-deadline-main.c:767
 dd_insert_requests+0xfe/0x170 block/mq-deadline-main.c:787
 blk_mq_sched_insert_request+0x1fc/0x250 block/blk-mq-sched.c:470
 blk_mq_submit_bio+0x524/0xe80 block/blk-mq.c:2263
 __submit_bio_noacct_mq block/blk-core.c:1011 [inline]
 submit_bio_noacct+0x6f2/0x7e0 block/blk-core.c:1044
 submit_bio+0x10c/0x190 include/linux/vmstat.h:81
 submit_bh_wbc+0x2f3/0x330 fs/buffer.c:3050
 submit_bh fs/buffer.c:3056 [inline]
 __sync_dirty_buffer+0x136/0x1e0 fs/buffer.c:3151
 sync_dirty_buffer+0x16/0x20 fs/buffer.c:3164
 __fat_write_inode+0x4c4/0x510 fs/fat/inode.c:899
 fat_write_inode+0xb9/0xd0 fs/fat/inode.c:915
 write_inode+0x89/0x180 fs/fs-writeback.c:1466
 __writeback_single_inode+0x2a2/0x440 fs/fs-writeback.c:1671
 writeback_single_inode+0x17b/0x3c0 fs/fs-writeback.c:1726
 sync_inode fs/fs-writeback.c:2745 [inline]
 sync_inode_metadata+0x57/0x80 fs/fs-writeback.c:2765
 __generic_file_fsync+0xf5/0x140 fs/libfs.c:1099
 fat_file_fsync+0x48/0x100 fs/fat/file.c:190
 vfs_fsync_range+0x107/0x120 fs/sync.c:200
 generic_write_sync include/linux/fs.h:2987 [inline]
 generic_file_write_iter+0x103/0x130 mm/filemap.c:3819
 call_write_iter include/linux/fs.h:2114 [inline]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
 do_iter_write+0x112/0x4c0 fs/read_write.c:866
 vfs_iter_write+0x4c/0x70 fs/read_write.c:907
 iter_file_splice_write+0x40a/0x750 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:936
 splice_direct_to_actor+0x345/0x650 fs/splice.c:891
 do_splice_direct+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x773/0xda0 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1325 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1311
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888237d376c8 of 8 bytes by task 6009 on cpu 0:
 try_to_del_timer_sync+0xe3/0x290 kernel/time/timer.c:1233
 del_timer_sync kernel/time/timer.c:1380 [inline]
 schedule_timeout+0x108/0x240 kernel/time/timer.c:1880
 schedule_timeout_uninterruptible+0x2c/0x30 kernel/time/timer.c:1913
 snd_use_lock_sync_helper+0x7d/0xf0 sound/core/seq/seq_lock.c:23
 snd_seq_fifo_clear+0x39/0x160 sound/core/seq/seq_fifo.c:90
 snd_seq_ioctl_remove_events+0x79/0xd0 sound/core/seq/seq_clientmgr.c:1920
 snd_seq_ioctl+0x156/0x250 sound/core/seq/seq_clientmgr.c:2173
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:1069 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:1055
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:1055
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0xffffc90000603cc8 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 6009 Comm: syz-executor.2 Not tainted 5.14.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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