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BUG: KCSAN: data-race in relay_switch_subbuf / relay_switch_subbuf

write to 0xffff888136161638 of 8 bytes by interrupt on cpu 1:
 relay_switch_subbuf+0x39e/0x3b0 kernel/relay.c:708
 relay_reserve include/linux/relay.h:248 [inline]
 __blk_add_trace+0x66a/0x730 kernel/trace/blktrace.c:276
 blk_add_trace_rq kernel/trace/blktrace.c:844 [inline]
 blk_add_trace_rq_complete+0x1b7/0x1c0 kernel/trace/blktrace.c:876
 trace_block_rq_complete include/trace/events/block.h:149 [inline]
 blk_update_request+0x8f8/0x950 block/blk-mq.c:894
 scsi_end_request+0x52/0x4f0 drivers/scsi/scsi_lib.c:631
 scsi_io_completion+0x9f/0x200 drivers/scsi/scsi_lib.c:1069
 scsi_finish_command+0x1be/0x1d0 drivers/scsi/scsi.c:198
 scsi_complete+0x19a/0x1d0 drivers/scsi/scsi_lib.c:1531
 blk_complete_reqs block/blk-mq.c:1129 [inline]
 blk_done_softirq+0x74/0xb0 block/blk-mq.c:1134
 __do_softirq+0xc8/0x285 kernel/softirq.c:554
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu kernel/softirq.c:633 [inline]
 irq_exit_rcu+0x3c/0x90 kernel/softirq.c:645
 common_interrupt+0x81/0x90 arch/x86/kernel/irq.c:247
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
 kcsan_setup_watchpoint+0x404/0x410 kernel/kcsan/core.c:705
 inet_twsk_purge+0x4e/0x3d0 net/ipv4/inet_timewait_sock.c:274
 dccp_v4_exit_batch+0x1a/0x20 net/dccp/ipv4.c:1042
 ops_exit_list net/core/net_namespace.c:175 [inline]
 cleanup_net+0x4cf/0x830 net/core/net_namespace.c:637
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0x465/0x990 kernel/workqueue.c:3335
 worker_thread+0x526/0x730 kernel/workqueue.c:3416
 kthread+0x1d1/0x210 kernel/kthread.c:388
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243

write to 0xffff888136161638 of 8 bytes by task 2415 on cpu 0:
 relay_switch_subbuf+0x39e/0x3b0 kernel/relay.c:708
 relay_reserve include/linux/relay.h:248 [inline]
 __blk_add_trace+0x66a/0x730 kernel/trace/blktrace.c:276
 blk_add_trace_bio kernel/trace/blktrace.c:903 [inline]
 blk_add_trace_bio_queue+0x130/0x140 kernel/trace/blktrace.c:935
 trace_block_bio_queue include/trace/events/block.h:383 [inline]
 submit_bio_noacct_nocheck+0x66b/0x6d0 block/blk-core.c:710
 submit_bio_noacct+0x681/0x830 block/blk-core.c:837
 submit_bio+0x218/0x230 block/blk-core.c:879
 swap_read_folio_bdev_async mm/page_io.c:492 [inline]
 swap_read_folio+0x4eb/0xc30 mm/page_io.c:526
 swap_cluster_readahead+0x3d1/0x3f0 mm/swap_state.c:701
 swapin_readahead+0xe2/0x7a0 mm/swap_state.c:904
 do_swap_page+0x3bb/0x15f0 mm/memory.c:4048
 handle_pte_fault mm/memory.c:5303 [inline]
 __handle_mm_fault mm/memory.c:5441 [inline]
 handle_mm_fault+0x7fa/0x27e0 mm/memory.c:5606
 do_user_addr_fault arch/x86/mm/fault.c:1362 [inline]
 handle_page_fault arch/x86/mm/fault.c:1505 [inline]
 exc_page_fault+0x3eb/0x6d0 arch/x86/mm/fault.c:1563
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

value changed: 0x0000000000000040 -> 0x0000000000000030

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 2415 Comm: syz-executor.0 Tainted: G        W          6.9.0-rc2-syzkaller-00002-g026e680b0a08 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
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