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BUG: KCSAN: data-race in relay_switch_subbuf / relay_switch_subbuf

write to 0xffff88812a79bc38 of 8 bytes by interrupt 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_rq kernel/trace/blktrace.c:844 [inline]
 blk_add_trace_rq_complete+0x1b3/0x1c0 kernel/trace/blktrace.c:876
 trace_block_rq_complete include/trace/events/block.h:149 [inline]
 blk_update_request+0x8f4/0x950 block/blk-mq.c:900
 scsi_end_request+0x52/0x4e0 drivers/scsi/scsi_lib.c:537
 scsi_io_completion+0x9f/0x200 drivers/scsi/scsi_lib.c:975
 scsi_finish_command+0x1bb/0x1d0 drivers/scsi/scsi.c:198
 scsi_complete+0x19a/0x1d0 drivers/scsi/scsi_lib.c:1437
 blk_complete_reqs block/blk-mq.c:1135 [inline]
 blk_done_softirq+0x73/0xa0 block/blk-mq.c:1140
 __do_softirq+0xc4/0x27b kernel/softirq.c:553
 invoke_softirq kernel/softirq.c:427 [inline]
 __irq_exit_rcu kernel/softirq.c:632 [inline]
 irq_exit_rcu+0x3b/0x90 kernel/softirq.c:644
 common_interrupt+0x81/0x90 arch/x86/kernel/irq.c:247
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:640
 kcsan_setup_watchpoint+0x3fe/0x410 kernel/kcsan/core.c:705
 crc32_body lib/crc32.c:87 [inline]
 crc32_le_generic lib/crc32.c:179 [inline]
 __crc32c_le_base+0x393/0x520 lib/crc32.c:201
 chksum_update+0x32/0x50 crypto/crc32c_generic.c:88
 crypto_shash_update+0x46/0x50 crypto/shash.c:70
 ext4_chksum fs/ext4/ext4.h:2476 [inline]
 ext4_inode_csum+0x1cf/0x4b0 fs/ext4/inode.c:64
 ext4_inode_csum_set fs/ext4/inode.c:115 [inline]
 ext4_fill_raw_inode+0xd48/0xe90 fs/ext4/inode.c:4322
 ext4_do_update_inode fs/ext4/inode.c:5079 [inline]
 ext4_mark_iloc_dirty+0x2e9/0xe10 fs/ext4/inode.c:5709
 __ext4_mark_inode_dirty+0x314/0x440 fs/ext4/inode.c:5913
 ext4_mkdir+0x344/0x740 fs/ext4/namei.c:3027
 vfs_mkdir+0x1ef/0x2f0 fs/namei.c:4122
 do_mkdirat+0x12f/0x2a0 fs/namei.c:4145
 __do_sys_mkdirat fs/namei.c:4160 [inline]
 __se_sys_mkdirat fs/namei.c:4158 [inline]
 __x64_sys_mkdirat+0x50/0x60 fs/namei.c:4158
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

write to 0xffff88812a79bc38 of 8 bytes by task 23675 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_rq kernel/trace/blktrace.c:844 [inline]
 blk_add_trace_rq_insert+0x1b6/0x1c0 kernel/trace/blktrace.c:851
 trace_block_rq_insert include/trace/events/block.h:215 [inline]
 dd_insert_request block/mq-deadline.c:824 [inline]
 dd_insert_requests+0x52e/0x670 block/mq-deadline.c:878
 blk_mq_dispatch_plug_list block/blk-mq.c:2783 [inline]
 blk_mq_flush_plug_list+0x634/0xdc0 block/blk-mq.c:2833
 blk_add_rq_to_plug+0x102/0x3d0 block/blk-mq.c:1299
 blk_mq_submit_bio+0x5c8/0xe30 block/blk-mq.c:3027
 __submit_bio+0x11c/0x350 block/blk-core.c:608
 __submit_bio_noacct_mq block/blk-core.c:687 [inline]
 submit_bio_noacct_nocheck+0x4ad/0x5e0 block/blk-core.c:716
 submit_bio_noacct+0x67d/0x830 block/blk-core.c:826
 submit_bio+0x212/0x220 block/blk-core.c:868
 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+0x8dd/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
 do_iter_readv_writev+0x2b0/0x330
 vfs_writev+0x2e9/0x860 fs/read_write.c:971
 do_pwritev fs/read_write.c:1072 [inline]
 __do_sys_pwritev2 fs/read_write.c:1131 [inline]
 __se_sys_pwritev2+0x10c/0x1d0 fs/read_write.c:1122
 __x64_sys_pwritev2+0x78/0x90 fs/read_write.c:1122
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0000000000000038 -> 0x0000000000000030

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 23675 Comm: syz-executor.4 Not tainted 6.8.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
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