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BUG: KCSAN: data-race in relay_switch_subbuf / relay_switch_subbuf

write to 0xffff88812a51e438 of 8 bytes by task 13748 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_issue+0xf8/0x110 kernel/trace/blktrace.c:850
 trace_block_rq_issue include/trace/events/block.h:204 [inline]
 blk_mq_start_request+0x247/0x290 block/blk-mq.c:1007
 scsi_queue_rq+0x11e2/0x14d0 drivers/scsi/scsi_lib.c:1698
 blk_mq_dispatch_rq_list+0x534/0x11d0 block/blk-mq.c:1639
 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:199 [inline]
 blk_mq_do_dispatch_sched+0x446/0x6d0 block/blk-mq-sched.c:212
 __blk_mq_sched_dispatch_requests+0x1ca/0x270
 blk_mq_sched_dispatch_requests+0x9f/0x110 block/blk-mq-sched.c:358
 __blk_mq_run_hw_queue+0xc1/0x140 block/blk-mq.c:1761
 __blk_mq_delay_run_hw_queue+0x199/0x360 block/blk-mq.c:1838
 blk_mq_run_hw_queue+0x231/0x260 block/blk-mq.c:1891
 blk_mq_sched_insert_requests+0x130/0x200 block/blk-mq-sched.c:508
 blk_mq_flush_plug_list+0x372/0x460 block/blk-mq.c:2268
 blk_mq_submit_bio+0x8de/0x1100 block/blk-mq.c:2579
 __submit_bio+0x41f/0x480 block/blk-core.c:873
 __submit_bio_noacct_mq block/blk-core.c:951 [inline]
 submit_bio_noacct+0x475/0x4e0 block/blk-core.c:977
 submit_bio+0x10c/0x180
 iomap_dio_submit_bio fs/iomap/direct-io.c:65 [inline]
 iomap_dio_bio_iter+0x9ed/0xc70 fs/iomap/direct-io.c:350
 __iomap_dio_rw+0x8b5/0x1070 fs/iomap/direct-io.c:589
 iomap_dio_rw+0x38/0x80 fs/iomap/direct-io.c:679
 ext4_dio_write_iter fs/ext4/file.c:568 [inline]
 ext4_file_write_iter+0xa72/0x1200 fs/ext4/file.c:679
 call_write_iter include/linux/fs.h:2161 [inline]
 do_iter_readv_writev+0x2de/0x380 fs/read_write.c:725
 do_iter_write+0x192/0x5c0 fs/read_write.c:851
 vfs_writev fs/read_write.c:924 [inline]
 do_pwritev+0x235/0x440 fs/read_write.c:1021
 __do_sys_pwritev2 fs/read_write.c:1080 [inline]
 __se_sys_pwritev2 fs/read_write.c:1071 [inline]
 __x64_sys_pwritev2+0x7e/0xa0 fs/read_write.c:1071
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

write to 0xffff88812a51e438 of 8 bytes by task 13747 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_bio kernel/trace/blktrace.c:896 [inline]
 blk_add_trace_getrq+0xb1/0xc0 kernel/trace/blktrace.c:933
 trace_block_getrq include/trace/events/block.h:343 [inline]
 blk_mq_submit_bio+0xe38/0x1100 block/blk-mq.c:2540
 __submit_bio+0x41f/0x480 block/blk-core.c:873
 __submit_bio_noacct_mq block/blk-core.c:951 [inline]
 submit_bio_noacct+0x475/0x4e0 block/blk-core.c:977
 submit_bio+0x10c/0x180
 iomap_dio_submit_bio fs/iomap/direct-io.c:65 [inline]
 iomap_dio_bio_iter+0x9ed/0xc70 fs/iomap/direct-io.c:350
 __iomap_dio_rw+0x8b5/0x1070 fs/iomap/direct-io.c:589
 iomap_dio_rw+0x38/0x80 fs/iomap/direct-io.c:679
 ext4_dio_write_iter fs/ext4/file.c:568 [inline]
 ext4_file_write_iter+0xa72/0x1200 fs/ext4/file.c:679
 call_write_iter include/linux/fs.h:2161 [inline]
 do_iter_readv_writev+0x2de/0x380 fs/read_write.c:725
 do_iter_write+0x192/0x5c0 fs/read_write.c:851
 vfs_writev fs/read_write.c:924 [inline]
 do_pwritev+0x235/0x440 fs/read_write.c:1021
 __do_sys_pwritev2 fs/read_write.c:1080 [inline]
 __se_sys_pwritev2 fs/read_write.c:1071 [inline]
 __x64_sys_pwritev2+0x7e/0xa0 fs/read_write.c:1071
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000000038 -> 0x0000000000000030

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 13747 Comm: syz-executor.3 Tainted: G        W         5.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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