The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x af98b0157adf6504fade79b3e6cb260c4ff68e37 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025062052-vigorous-overlaid-8bec@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From af98b0157adf6504fade79b3e6cb260c4ff68e37 Mon Sep 17 00:00:00 2001 From: Jeongjun Park aha310510@gmail.com Date: Wed, 14 May 2025 22:08:55 +0900 Subject: [PATCH] jbd2: fix data-race and null-ptr-deref in jbd2_journal_dirty_metadata()

Since handle->h_transaction may be a NULL pointer, so we should change it to call is_handle_aborted(handle) first before dereferencing it.

And the following data-race was reported in my fuzzer:

================================================================== BUG: KCSAN: data-race in jbd2_journal_dirty_metadata / jbd2_journal_dirty_metadata

write to 0xffff888011024104 of 4 bytes by task 10881 on cpu 1: jbd2_journal_dirty_metadata+0x2a5/0x770 fs/jbd2/transaction.c:1556 __ext4_handle_dirty_metadata+0xe7/0x4b0 fs/ext4/ext4_jbd2.c:358 ext4_do_update_inode fs/ext4/inode.c:5220 [inline] ext4_mark_iloc_dirty+0x32c/0xd50 fs/ext4/inode.c:5869 __ext4_mark_inode_dirty+0xe1/0x450 fs/ext4/inode.c:6074 ext4_dirty_inode+0x98/0xc0 fs/ext4/inode.c:6103 ....

read to 0xffff888011024104 of 4 bytes by task 10880 on cpu 0: jbd2_journal_dirty_metadata+0xf2/0x770 fs/jbd2/transaction.c:1512 __ext4_handle_dirty_metadata+0xe7/0x4b0 fs/ext4/ext4_jbd2.c:358 ext4_do_update_inode fs/ext4/inode.c:5220 [inline] ext4_mark_iloc_dirty+0x32c/0xd50 fs/ext4/inode.c:5869 __ext4_mark_inode_dirty+0xe1/0x450 fs/ext4/inode.c:6074 ext4_dirty_inode+0x98/0xc0 fs/ext4/inode.c:6103 ....

value changed: 0x00000000 -> 0x00000001 ==================================================================

This issue is caused by missing data-race annotation for jh->b_modified. Therefore, the missing annotation needs to be added.

Reported-by: syzbot+de24c3fe3c4091051710@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=de24c3fe3c4091051710 Fixes: 6e06ae88edae ("jbd2: speedup jbd2_journal_dirty_metadata()") Signed-off-by: Jeongjun Park aha310510@gmail.com Reviewed-by: Jan Kara jack@suse.cz Link: https://patch.msgid.link/20250514130855.99010-1-aha310510@gmail.com Signed-off-by: Theodore Ts'o tytso@mit.edu Cc: stable@kernel.org

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c index cbc4785462f5..c7867139af69 100644 --- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -1509,7 +1509,7 @@ int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh) jh->b_next_transaction == transaction); spin_unlock(&jh->b_state_lock); } - if (jh->b_modified == 1) { + if (data_race(jh->b_modified == 1)) { /* If it's in our transaction it must be in BJ_Metadata list. */ if (data_race(jh->b_transaction == transaction && jh->b_jlist != BJ_Metadata)) { @@ -1528,7 +1528,6 @@ int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh) goto out; }

- journal = transaction->t_journal; spin_lock(&jh->b_state_lock);

if (is_handle_aborted(handle)) { @@ -1543,6 +1542,8 @@ int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh) goto out_unlock_bh; }

+ journal = transaction->t_journal; + if (jh->b_modified == 0) { /* * This buffer's got modified and becoming part