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BUG: KCSAN: data-race in relay_switch_subbuf / relay_switch_subbuf

write to 0xffff888131cdcc38 of 8 bytes by task 29910 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:551 [inline]
 submit_bio_noacct+0x846/0x8a0 block/blk-core.c:742
 submit_bio+0xb7/0xc0 block/blk-core.c:834
 swap_writepage_bdev_async mm/page_io.c:368 [inline]
 __swap_writepage+0x625/0xc90 mm/page_io.c:386
 swap_writepage+0x6e/0x120 mm/page_io.c:204
 pageout mm/vmscan.c:1355 [inline]
 shrink_folio_list+0x1952/0x2540 mm/vmscan.c:2015
 reclaim_folio_list+0x7b/0x1d0 mm/vmscan.c:2801
 reclaim_pages+0x220/0x280 mm/vmscan.c:2837
 madvise_cold_or_pageout_pte_range+0x98c/0x9f0 mm/madvise.c:533
 walk_pmd_range mm/pagewalk.c:143 [inline]
 walk_pud_range mm/pagewalk.c:221 [inline]
 walk_p4d_range mm/pagewalk.c:256 [inline]
 walk_pgd_range+0x80a/0xec0 mm/pagewalk.c:293
 __walk_page_range+0xc2/0x320 mm/pagewalk.c:395
 walk_page_range+0x2c7/0x3f0 mm/pagewalk.c:521
 madvise_pageout_page_range mm/madvise.c:592 [inline]
 madvise_pageout mm/madvise.c:619 [inline]
 madvise_vma_behavior mm/madvise.c:1041 [inline]
 madvise_walk_vmas mm/madvise.c:1270 [inline]
 do_madvise+0x1f20/0x2970 mm/madvise.c:1450
 __do_sys_madvise mm/madvise.c:1463 [inline]
 __se_sys_madvise mm/madvise.c:1461 [inline]
 __x64_sys_madvise+0x60/0x70 mm/madvise.c:1461
 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 0xffff888131cdcc38 of 8 bytes by task 29916 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:690
 submit_bio_noacct+0x700/0x8a0 block/blk-core.c:801
 submit_bio+0xb7/0xc0 block/blk-core.c:834
 swap_writepage_bdev_async mm/page_io.c:368 [inline]
 __swap_writepage+0x625/0xc90 mm/page_io.c:386
 swap_writepage+0x6e/0x120 mm/page_io.c:204
 pageout mm/vmscan.c:1355 [inline]
 shrink_folio_list+0x1952/0x2540 mm/vmscan.c:2015
 reclaim_folio_list+0x7b/0x1d0 mm/vmscan.c:2801
 reclaim_pages+0x220/0x280 mm/vmscan.c:2837
 madvise_cold_or_pageout_pte_range+0x98c/0x9f0 mm/madvise.c:533
 walk_pmd_range mm/pagewalk.c:143 [inline]
 walk_pud_range mm/pagewalk.c:221 [inline]
 walk_p4d_range mm/pagewalk.c:256 [inline]
 walk_pgd_range+0x80a/0xec0 mm/pagewalk.c:293
 __walk_page_range+0xc2/0x320 mm/pagewalk.c:395
 walk_page_range+0x2c7/0x3f0 mm/pagewalk.c:521
 madvise_pageout_page_range mm/madvise.c:592 [inline]
 madvise_pageout mm/madvise.c:619 [inline]
 madvise_vma_behavior mm/madvise.c:1041 [inline]
 madvise_walk_vmas mm/madvise.c:1270 [inline]
 do_madvise+0x1f20/0x2970 mm/madvise.c:1450
 __do_sys_madvise mm/madvise.c:1463 [inline]
 __se_sys_madvise mm/madvise.c:1461 [inline]
 __x64_sys_madvise+0x60/0x70 mm/madvise.c:1461
 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

value changed: 0x0000000000000040 -> 0x0000000000000030

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 29916 Comm: syz-executor.5 Tainted: G        W          6.6.0-rc2-syzkaller-00309-g8018e02a8703 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023
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