loop5: detected capacity change from 0 to 8192
==================================================================
BUG: KCSAN: data-race in relay_switch_subbuf / relay_switch_subbuf

write to 0xffff888103504238 of 8 bytes by task 3291 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_plug+0x4c/0x70 kernel/trace/blktrace.c:949
 trace_block_plug include/trace/events/block.h:430 [inline]
 blk_add_rq_to_plug+0x31b/0x3d0 block/blk-mq.c:1378
 blk_mq_submit_bio+0x96c/0xe40 block/blk-mq.c:3148
 __submit_bio+0xf2/0x470 block/blk-core.c:629
 __submit_bio_noacct_mq block/blk-core.c:710 [inline]
 submit_bio_noacct_nocheck+0x295/0x6e0 block/blk-core.c:739
 submit_bio_noacct+0x766/0x9a0 block/blk-core.c:868
 submit_bio+0x218/0x230 block/blk-core.c:910
 submit_bh_wbc+0x2ed/0x330 fs/buffer.c:2814
 submit_bh fs/buffer.c:2819 [inline]
 block_read_full_folio+0x663/0x6f0 fs/buffer.c:2446
 blkdev_read_folio+0x1c/0x30 block/fops.c:442
 filemap_read_folio mm/filemap.c:2366 [inline]
 filemap_update_page mm/filemap.c:2450 [inline]
 filemap_get_pages+0xddc/0x10e0 mm/filemap.c:2571
 filemap_read+0x221/0x6a0 mm/filemap.c:2646
 blkdev_read_iter+0x20e/0x2c0 block/fops.c:770
 new_sync_read fs/read_write.c:484 [inline]
 vfs_read+0x5dc/0x700 fs/read_write.c:565
 ksys_read+0xe8/0x1b0 fs/read_write.c:708
 __do_sys_read fs/read_write.c:717 [inline]
 __se_sys_read fs/read_write.c:715 [inline]
 __x64_sys_read+0x42/0x50 fs/read_write.c:715
 x64_sys_call+0x2874/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

write to 0xffff888103504238 of 8 bytes by task 7022 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_unplug+0x76/0xb0 kernel/trace/blktrace.c:969
 trace_block_unplug include/trace/events/block.h:475 [inline]
 blk_mq_flush_plug_list+0xe9c/0xef0 block/blk-mq.c:2893
 __blk_flush_plug+0x216/0x290 block/blk-core.c:1213
 blk_finish_plug block/blk-core.c:1240 [inline]
 __submit_bio+0x280/0x470 block/blk-core.c:637
 __submit_bio_noacct_mq block/blk-core.c:710 [inline]
 submit_bio_noacct_nocheck+0x295/0x6e0 block/blk-core.c:739
 submit_bio_noacct+0x766/0x9a0 block/blk-core.c:868
 submit_bio+0x218/0x230 block/blk-core.c:910
 submit_bh_wbc+0x2ed/0x330 fs/buffer.c:2814
 submit_bh fs/buffer.c:2819 [inline]
 __bread_slow fs/buffer.c:1264 [inline]
 __bread_gfp+0x17c/0x280 fs/buffer.c:1488
 sb_bread include/linux/buffer_head.h:346 [inline]
 fat__get_entry fs/fat/dir.c:100 [inline]
 fat_get_entry+0x482/0x5f0 fs/fat/dir.c:128
 fat_get_short_entry fs/fat/dir.c:885 [inline]
 fat_subdirs+0xfa/0x190 fs/fat/dir.c:951
 fat_read_root+0x31d/0x360 fs/fat/inode.c:1345
 fat_fill_super+0x14f5/0x1bf0 fs/fat/inode.c:1814
 vfat_fill_super+0x24/0x30 fs/fat/namei_vfat.c:1200
 get_tree_bdev_flags+0x29f/0x310 fs/super.c:1636
 get_tree_bdev+0x1f/0x30 fs/super.c:1659
 vfat_get_tree+0x1c/0x30 fs/fat/namei_vfat.c:1205
 vfs_get_tree+0x56/0x1e0 fs/super.c:1814
 do_new_mount+0x227/0x690 fs/namespace.c:3507
 path_mount+0x49b/0xb30 fs/namespace.c:3834
 do_mount fs/namespace.c:3847 [inline]
 __do_sys_mount fs/namespace.c:4057 [inline]
 __se_sys_mount+0x27c/0x2d0 fs/namespace.c:4034
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4034
 x64_sys_call+0x2c84/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000030 -> 0x0000000000000038

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 7022 Comm: syz.5.985 Not tainted 6.13.0-rc2-syzkaller-00192-g243f750a2df0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================