Hi:

When using Healer(https://github.com/SunHao-0/healer/tree/dev) to fuzz
the Linux kernel, I found a data-race vulnerability in
__jbd2_journal_file_buffer / jbd2_journal_dirty_metadata.
Sorry, data-race is usually difficult to reproduce. I cannot provide
you with a reproducing program.
I hope that the call stack information in the crash log can help you
locate the problem.
Kernel config and full log can be found in the attachment.

Here is the detailed information:
commit:   3b9cdafb5358eb9f3790de2f728f765fef100731
version:   linux 5.11
git tree:    upstream
report:
==================================================================
BUG: KCSAN: data-race in __jbd2_journal_file_buffer /
jbd2_journal_dirty_metadata
write to 0xffff88800af6da38 of 8 bytes by task 4822 on cpu 1:
 __jbd2_journal_file_buffer+0x18d/0x370 linux/fs/jbd2/transaction.c:2518
 __jbd2_journal_refile_buffer+0x155/0x230 linux/fs/jbd2/transaction.c:2612
 jbd2_journal_commit_transaction+0x24c6/0x3200 linux/fs/jbd2/commit.c:1084
 kjournald2+0x253/0x470 linux/fs/jbd2/journal.c:213
 kthread+0x1f0/0x220 linux/kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 linux/arch/x86/entry/entry_64.S:294