==================================================================
BUG: KCSAN: data-race in relay_switch_subbuf / relay_switch_subbuf

write to 0xffff88813aa0ee38 of 8 bytes by task 2743 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 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:698
 submit_bio_noacct+0x70c/0x8c0 block/blk-core.c:809
 submit_bio+0xb7/0xc0 block/blk-core.c:842
 submit_bh_wbc+0x2ca/0x300 fs/buffer.c:2821
 submit_bh+0x1c/0x20 fs/buffer.c:2826
 jbd2_journal_commit_transaction+0x15f0/0x33a0 fs/jbd2/commit.c:731
 kjournald2+0x242/0x420 fs/jbd2/journal.c:201
 kthread+0x1d7/0x210 kernel/kthread.c:388
 ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242

write to 0xffff88813aa0ee38 of 8 bytes by task 10220 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_unplug+0x76/0xb0 kernel/trace/blktrace.c:970
 trace_block_unplug include/trace/events/block.h:452 [inline]
 blk_mq_dispatch_plug_list block/blk-mq.c:2752 [inline]
 blk_mq_flush_plug_list+0xd09/0xdc0 block/blk-mq.c:2812
 __blk_flush_plug+0x210/0x260 block/blk-core.c:1150
 blk_flush_plug include/linux/blkdev.h:995 [inline]
 io_schedule_prepare kernel/sched/core.c:8967 [inline]
 io_schedule+0x36/0x60 kernel/sched/core.c:8997
 bit_wait_io+0xc/0x50 kernel/sched/wait_bit.c:209
 __wait_on_bit+0xcb/0x160 kernel/sched/wait_bit.c:49
 out_of_line_wait_on_bit+0x96/0xb0 kernel/sched/wait_bit.c:64
 wait_on_bit_io include/linux/wait_bit.h:101 [inline]
 do_get_write_access+0xc2/0x8b0 fs/jbd2/transaction.c:1111
 jbd2_journal_get_write_access+0x110/0x1c0 fs/jbd2/transaction.c:1246
 __ext4_journal_get_write_access+0x154/0x3f0 fs/ext4/ext4_jbd2.c:241
 ext4_reserve_inode_write+0x14e/0x200 fs/ext4/inode.c:5754
 __ext4_mark_inode_dirty+0x8e/0x440 fs/ext4/inode.c:5928
 ext4_dirty_inode+0x91/0xb0 fs/ext4/inode.c:5965
 __mark_inode_dirty+0x169/0x7d0 fs/fs-writeback.c:2452
 mark_inode_dirty include/linux/fs.h:2306 [inline]
 dquot_alloc_space include/linux/quotaops.h:320 [inline]
 dquot_alloc_block include/linux/quotaops.h:337 [inline]
 ext4_mb_new_blocks+0x103e/0x21e0 fs/ext4/mballoc.c:6157
 ext4_ext_map_blocks+0x1086/0x3640 fs/ext4/extents.c:4285
 ext4_map_blocks+0x704/0xf60 fs/ext4/inode.c:621
 ext4_iomap_alloc fs/ext4/inode.c:3320 [inline]
 ext4_iomap_begin+0x4a9/0x5d0 fs/ext4/inode.c:3370
 iomap_iter+0x401/0x820 fs/iomap/iter.c:91
 __iomap_dio_rw+0xb63/0x1090 fs/iomap/direct-io.c:658
 iomap_dio_rw+0x40/0x90 fs/iomap/direct-io.c:748
 ext4_dio_write_iter fs/ext4/file.c:577 [inline]
 ext4_file_write_iter+0xa8a/0xe10 fs/ext4/file.c:696
 call_write_iter include/linux/fs.h:2020 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x48a/0x790 fs/read_write.c:584
 ksys_write+0xeb/0x1a0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0000000000000040 -> 0x0000000000000030

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 10220 Comm: syz-executor.0 Not tainted 6.7.0-rc5-syzkaller-00134-g3f7168591ebf #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
==================================================================
syz-executor.0 (10220) used greatest stack depth: 9040 bytes left