From: Jeongjun Park <aha310510@gmail.com>
To: stable@vger.kernel.org
Cc: tytso@mit.edu, jack@suse.com, linux-ext4@vger.kernel.org,
linux-kernel@vger.kernel.org,
syzbot+de24c3fe3c4091051710@syzkaller.appspotmail.com,
Jeongjun Park <aha310510@gmail.com>, Jan Kara <jack@suse.cz>,
stable@kernel.org
Subject: [PATCH 5.4.y] jbd2: fix data-race and null-ptr-deref in jbd2_journal_dirty_metadata()
Date: Fri, 20 Jun 2025 17:49:58 +0900 [thread overview]
Message-ID: <20250620084958.26672-1-aha310510@gmail.com> (raw)
In-Reply-To: <2025062052-vigorous-overlaid-8bec@gregkh>
commit af98b0157adf6504fade79b3e6cb260c4ff68e37 upstream.
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
---
fs/jbd2/transaction.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index 91c2d3f6d1b3..72e9297d6adc 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1419,7 +1419,6 @@ int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)
goto out;
}
- journal = transaction->t_journal;
jbd_lock_bh_state(bh);
if (is_handle_aborted(handle)) {
@@ -1434,6 +1433,8 @@ 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
--
next prev parent reply other threads:[~2025-06-20 8:50 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-20 7:33 FAILED: patch "[PATCH] jbd2: fix data-race and null-ptr-deref in" failed to apply to 5.4-stable tree gregkh
2025-06-20 8:49 ` Jeongjun Park [this message]
2025-06-21 8:52 ` [PATCH 5.4.y] jbd2: fix data-race and null-ptr-deref in jbd2_journal_dirty_metadata() Sasha Levin
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