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BUG: KCSAN: data-race in relay_switch_subbuf / relay_switch_subbuf

write to 0xffff888135ffb438 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]
 trace_note+0x34e/0x3d0 kernel/trace/blktrace.c:95
 trace_note_tsk+0x9c/0xe0 kernel/trace/blktrace.c:126
 __blk_add_trace+0x649/0x720 kernel/trace/blktrace.c:268
 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:539
 scsi_io_completion+0x9f/0x200 drivers/scsi/scsi_lib.c:977
 scsi_finish_command+0x1bb/0x1d0 drivers/scsi/scsi.c:198
 scsi_complete+0x19a/0x1d0 drivers/scsi/scsi_lib.c:1439
 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
 mas_next_slot+0xbe5/0xc40
 mas_find+0x2c0/0x360 lib/maple_tree.c:6020
 vma_next include/linux/mm.h:961 [inline]
 acct_collect+0x116/0x440 kernel/acct.c:565
 do_exit+0x537/0x16d0 kernel/exit.c:850
 do_group_exit+0x101/0x150 kernel/exit.c:1020
 get_signal+0xf4e/0x10a0 kernel/signal.c:2893
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:105 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:201 [inline]
 syscall_exit_to_user_mode+0x58/0x130 kernel/entry/common.c:212
 do_syscall_64+0xda/0x1d0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

write to 0xffff888135ffb438 of 8 bytes by task 9652 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
 ext4_io_submit+0x8a/0xa0 fs/ext4/page-io.c:378
 ext4_do_writepages+0xb3a/0x2100 fs/ext4/inode.c:2699
 ext4_writepages+0x15e/0x2e0 fs/ext4/inode.c:2768
 do_writepages+0x1c2/0x340 mm/page-writeback.c:2553
 filemap_fdatawrite_wbc+0xdb/0xf0 mm/filemap.c:388
 __filemap_fdatawrite_range mm/filemap.c:421 [inline]
 filemap_write_and_wait_range+0xe0/0x210 mm/filemap.c:676
 filemap_write_and_wait include/linux/pagemap.h:64 [inline]
 ext4_bmap+0x14e/0x180 fs/ext4/inode.c:3109
 bmap+0x5a/0x80 fs/inode.c:1790
 ioctl_fibmap fs/ioctl.c:77 [inline]
 file_ioctl fs/ioctl.c:328 [inline]
 do_vfs_ioctl+0x11b5/0x13a0 fs/ioctl.c:850
 __do_sys_ioctl fs/ioctl.c:869 [inline]
 __se_sys_ioctl+0x81/0x140 fs/ioctl.c:857
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:857
 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: 9652 Comm: syz-executor.3 Not tainted 6.8.0-rc4-syzkaller-00005-gc664e16bb1ba #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
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