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BUG: KCSAN: data-race in relay_switch_subbuf / relay_switch_subbuf

write to 0xffff88813a5a9638 of 8 bytes by task 3221 on cpu 1:
 relay_switch_subbuf+0x399/0x3a0 kernel/relay.c:708
 relay_reserve include/linux/relay.h:248 [inline]
 __blk_add_trace+0x665/0x720 kernel/trace/blktrace.c:276
 blk_add_trace_bio_remap+0x161/0x170 kernel/trace/blktrace.c:1021
 trace_block_bio_remap include/trace/events/block.h:507 [inline]
 blk_partition_remap block/blk-core.c:559 [inline]
 submit_bio_noacct+0x7d6/0x830 block/blk-core.c:750
 submit_bio+0xb7/0xc0 block/blk-core.c:858
 iomap_dio_submit_bio fs/iomap/direct-io.c:80 [inline]
 iomap_dio_bio_iter+0xa4a/0xbe0 fs/iomap/direct-io.c:417
 __iomap_dio_rw+0x8db/0x1090 fs/iomap/direct-io.c:659
 iomap_dio_rw+0x40/0x90 fs/iomap/direct-io.c:748
 ext4_dio_write_iter fs/ext4/file.c:577 [inline]
 ext4_file_write_iter+0xa8a/0xe10 fs/ext4/file.c:696
 call_write_iter include/linux/fs.h:2085 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0x760/0x8d0 fs/read_write.c:590
 ksys_write+0xeb/0x1a0 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:652
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x59/0x120 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

write to 0xffff88813a5a9638 of 8 bytes by task 2726 on cpu 0:
 relay_switch_subbuf+0x399/0x3a0 kernel/relay.c:708
 relay_reserve include/linux/relay.h:248 [inline]
 __blk_add_trace+0x665/0x720 kernel/trace/blktrace.c:276
 blk_add_trace_bio kernel/trace/blktrace.c:903 [inline]
 blk_add_trace_bio_queue+0x12c/0x140 kernel/trace/blktrace.c:935
 trace_block_bio_queue include/trace/events/block.h:383 [inline]
 submit_bio_noacct_nocheck+0x57d/0x5e0 block/blk-core.c:698
 submit_bio_noacct+0x67d/0x830 block/blk-core.c:825
 submit_bio+0xb7/0xc0 block/blk-core.c:858
 submit_bh_wbc+0x2ca/0x300 fs/buffer.c:2800
 submit_bh+0x1c/0x20 fs/buffer.c:2805
 jbd2_journal_commit_transaction+0x15e7/0x33a0 fs/jbd2/commit.c:731
 kjournald2+0x242/0x420 fs/jbd2/journal.c:201
 kthread+0x1d7/0x210 kernel/kthread.c:388
 ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

value changed: 0x0000000000000040 -> 0x0000000000000030

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 2726 Comm: jbd2/sda1-8 Not tainted 6.8.0-rc1-syzkaller-00026-g7ed2632ec7d7 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
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