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BUG: KCSAN: data-race in relay_switch_subbuf / relay_switch_subbuf

write to 0xffff888150fbb438 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:147 [inline]
 blk_update_request+0x8fa/0x950 block/blk-mq.c:877
 scsi_end_request+0x52/0x4e0 drivers/scsi/scsi_lib.c:541
 scsi_io_completion+0x9f/0x200 drivers/scsi/scsi_lib.c:978
 scsi_finish_command+0x1bb/0x1d0 drivers/scsi/scsi.c:198
 scsi_complete+0x19a/0x1d0 drivers/scsi/scsi_lib.c:1442
 blk_complete_reqs block/blk-mq.c:1113 [inline]
 blk_done_softirq+0x73/0xa0 block/blk-mq.c:1118
 __do_softirq+0xc1/0x265 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+0x7f/0x90 arch/x86/kernel/irq.c:247
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:636
 _raw_spin_lock_irqsave+0x8/0xa0 kernel/locking/spinlock.c:161
 __skb_try_recv_datagram+0xf4/0x310 net/core/datagram.c:262
 __unix_dgram_recvmsg+0x25b/0x870 net/unix/af_unix.c:2362
 unix_dgram_recvmsg+0x7b/0x90 net/unix/af_unix.c:2459
 sock_recvmsg_nosec+0x4c/0x80 net/socket.c:1020
 ____sys_recvmsg+0x2db/0x310 net/socket.c:2711
 ___sys_recvmsg net/socket.c:2755 [inline]
 do_recvmmsg+0x2eb/0x720 net/socket.c:2849
 __sys_recvmmsg net/socket.c:2928 [inline]
 __do_sys_recvmmsg net/socket.c:2951 [inline]
 __se_sys_recvmmsg net/socket.c:2944 [inline]
 __x64_sys_recvmmsg+0xe2/0x160 net/socket.c:2944
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

write to 0xffff888150fbb438 of 8 bytes by task 24874 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:213 [inline]
 dd_insert_request block/mq-deadline.c:823 [inline]
 dd_insert_requests+0x529/0x670 block/mq-deadline.c:877
 blk_mq_dispatch_plug_list block/blk-mq.c:2744 [inline]
 blk_mq_flush_plug_list+0x67f/0xda0 block/blk-mq.c:2799
 blk_add_rq_to_plug+0x108/0x3e0 block/blk-mq.c:1279
 blk_mq_submit_bio+0x692/0xd70 block/blk-mq.c:2994
 __submit_bio+0x11c/0x350 block/blk-core.c:598
 __submit_bio_noacct_mq block/blk-core.c:677 [inline]
 submit_bio_noacct_nocheck+0x4ad/0x5e0 block/blk-core.c:706
 submit_bio_noacct+0x700/0x8a0 block/blk-core.c:800
 submit_bio+0xb7/0xc0 block/blk-core.c:833
 ext4_io_submit+0x8a/0xa0 fs/ext4/page-io.c:378
 ext4_do_writepages+0xb77/0x21e0 fs/ext4/inode.c:2697
 ext4_writepages+0x15e/0x2e0 fs/ext4/inode.c:2766
 do_writepages+0x1c5/0x340 mm/page-writeback.c:2553
 filemap_fdatawrite_wbc+0xdb/0xf0 mm/filemap.c:393
 __filemap_fdatawrite_range mm/filemap.c:426 [inline]
 __filemap_fdatawrite mm/filemap.c:432 [inline]
 filemap_flush+0x95/0xc0 mm/filemap.c:459
 ext4_alloc_da_blocks+0x50/0x130 fs/ext4/inode.c:3033
 ext4_release_file+0x5f/0x1c0 fs/ext4/file.c:169
 __fput+0x2fd/0x600 fs/file_table.c:384
 ____fput+0x15/0x20 fs/file_table.c:412
 task_work_run+0x135/0x1a0 kernel/task_work.c:179
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0x5ff/0x1670 kernel/exit.c:874
 do_group_exit+0x101/0x150 kernel/exit.c:1024
 get_signal+0xeb7/0xff0 kernel/signal.c:2881
 arch_do_signal_or_restart+0x89/0x2a0 arch/x86/kernel/signal.c:308
 exit_to_user_mode_loop+0x6f/0xe0 kernel/entry/common.c:168
 exit_to_user_mode_prepare+0x6c/0xb0 kernel/entry/common.c:204
 irqentry_exit_to_user_mode+0x9/0x20 kernel/entry/common.c:310
 irqentry_exit+0x12/0x40 kernel/entry/common.c:413
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570

value changed: 0x0000000000000038 -> 0x0000000000000030

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 24874 Comm: syz-executor.4 Tainted: G        W          6.5.0-rc5-syzkaller-00362-ga785fd28d31f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
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syz-executor.4 (24874) used greatest stack depth: 9464 bytes left