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BUG: KCSAN: data-race in relay_switch_subbuf / relay_switch_subbuf

write to 0xffff88813e511e38 of 8 bytes by interrupt on cpu 1:
 relay_switch_subbuf+0x3b5/0x3c0 kernel/relay.c:711
 relay_reserve include/linux/relay.h:248 [inline]
 __blk_add_trace+0x66f/0x740 kernel/trace/blktrace.c:275
 blk_add_trace_rq kernel/trace/blktrace.c:836 [inline]
 blk_add_trace_rq_complete+0x102/0x110 kernel/trace/blktrace.c:869
 trace_block_rq_complete include/trace/events/block.h:115 [inline]
 blk_update_request+0x8a9/0x8f0 block/blk-mq.c:780
 scsi_end_request+0x4b/0x460 drivers/scsi/scsi_lib.c:543
 scsi_io_completion+0xdf/0x1220 drivers/scsi/scsi_lib.c:980
 scsi_finish_command+0x1d0/0x1e0 drivers/scsi/scsi.c:198
 scsi_complete+0x1a5/0x1e0 drivers/scsi/scsi_lib.c:1482
 blk_complete_reqs block/blk-mq.c:999 [inline]
 blk_done_softirq+0x92/0xc0 block/blk-mq.c:1004
 __do_softirq+0x158/0x2de kernel/softirq.c:558
 __irq_exit_rcu kernel/softirq.c:637 [inline]
 irq_exit_rcu+0x37/0x70 kernel/softirq.c:649
 common_interrupt+0x9f/0xc0 arch/x86/kernel/irq.c:240
 asm_common_interrupt+0x1e/0x40
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
 _raw_spin_unlock_irqrestore+0x38/0x60 kernel/locking/spinlock.c:194
 spin_unlock_irqrestore include/linux/spinlock.h:404 [inline]
 __folio_end_writeback+0x3a1/0x580 mm/page-writeback.c:2836
 folio_end_writeback+0x57/0x130 mm/filemap.c:1644
 end_page_writeback+0x37/0x50 mm/folio-compat.c:25
 ext4_finish_bio+0x30e/0x360 fs/ext4/page-io.c:143
 ext4_release_io_end+0x5f/0x140 fs/ext4/page-io.c:158
 ext4_end_io_end fs/ext4/page-io.c:192 [inline]
 ext4_do_flush_completed_IO fs/ext4/page-io.c:257 [inline]
 ext4_end_io_rsv_work+0x1f6/0x240 fs/ext4/page-io.c:271
 process_one_work+0x3f6/0x960 kernel/workqueue.c:2307
 worker_thread+0x616/0xa70 kernel/workqueue.c:2454
 kthread+0x1bf/0x1e0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30

write to 0xffff88813e511e38 of 8 bytes by task 330 on cpu 0:
 relay_switch_subbuf+0x3b5/0x3c0 kernel/relay.c:711
 relay_reserve include/linux/relay.h:248 [inline]
 __blk_add_trace+0x66f/0x740 kernel/trace/blktrace.c:275
 blk_add_trace_rq kernel/trace/blktrace.c:836 [inline]
 blk_add_trace_rq_insert+0xf8/0x110 kernel/trace/blktrace.c:844
 trace_block_rq_insert include/trace/events/block.h:190 [inline]
 dd_insert_request+0x4ed/0x530 block/mq-deadline.c:741
 dd_insert_requests+0x10c/0x150 block/mq-deadline.c:777
 blk_mq_sched_insert_requests+0xc1/0x2a0 block/blk-mq-sched.c:470
 blk_mq_flush_plug_list+0x5c3/0x6c0 block/blk-mq.c:2628
 blk_add_rq_to_plug+0x13f/0x3a0 block/blk-mq.c:2690
 blk_mq_submit_bio+0x8c7/0xe50 block/blk-mq.c:2831
 __submit_bio+0x151/0x350 block/blk-core.c:806
 __submit_bio_noacct_mq block/blk-core.c:881 [inline]
 submit_bio_noacct+0x475/0x4e0 block/blk-core.c:907
 submit_bio+0x10c/0x180
 ext4_io_submit+0x5e/0x80 fs/ext4/page-io.c:379
 ext4_writepages+0x94a/0x1a60 fs/ext4/inode.c:2798
 do_writepages+0x1cb/0x330 mm/page-writeback.c:2364
 filemap_fdatawrite_wbc mm/filemap.c:384 [inline]
 __filemap_fdatawrite_range mm/filemap.c:417 [inline]
 __filemap_fdatawrite mm/filemap.c:423 [inline]
 filemap_flush+0xd9/0x100 mm/filemap.c:450
 ext4_release_file+0x4b/0x160 fs/ext4/file.c:141
 __fput+0x295/0x520 fs/file_table.c:311
 ____fput+0x11/0x20 fs/file_table.c:344
 task_work_run+0x8e/0x110 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x160/0x190 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
 do_syscall_64+0x50/0xd0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000000038 -> 0x0000000000000030

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 330 Comm: syz-executor.3 Not tainted 5.17.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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