The patch titled
Subject: ocfs2: fix null-ptr-deref when journal load failed.
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
ocfs2-fix-null-ptr-deref-when-journal-load-failed.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/ocfs2-fix-null-ptr-deref-when-journal-load-failed.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Julian Sun <sunjunchao2870@xxxxxxxxx>
Subject: ocfs2: fix null-ptr-deref when journal load failed.
Date: Mon, 2 Sep 2024 11:08:44 +0800
During the mounting process, if journal_reset() fails because of too short
journal, then lead to jbd2_journal_load() fails with NULL j_sb_buffer.
Subsequently, ocfs2_journal_shutdown() calls
jbd2_journal_flush()->jbd2_cleanup_journal_tail()->
__jbd2_update_log_tail()->jbd2_journal_update_sb_log_tail()
->lock_buffer(journal->j_sb_buffer), resulting in a null-pointer
dereference error.
To resolve this issue, we should check the JBD2_LOADED flag to ensure the
journal was properly loaded. Additionally, use journal instead of
osb->journal directly to simplify the code.
Link: https://syzkaller.appspot.com/bug?extid=05b9b39d8bdfe1a0861f
Link: https://lkml.kernel.org/r/20240902030844.422725-1-sunjunchao2870@xxxxxxxxx
Fixes: f6f50e28f0cb ("jbd2: Fail to load a journal if it is too short")
Signed-off-by: Julian Sun <sunjunchao2870@xxxxxxxxx>
Reported-by: syzbot+05b9b39d8bdfe1a0861f@xxxxxxxxxxxxxxxxxxxxxxxxx
Suggested-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
Reviewed-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
Cc: Mark Fasheh <mark@xxxxxxxxxx>
Cc: Joel Becker <jlbec@xxxxxxxxxxxx>
Cc: Junxiao Bi <junxiao.bi@xxxxxxxxxx>
Cc: Changwei Ge <gechangwei@xxxxxxx>
Cc: Gang He <ghe@xxxxxxxx>
Cc: Jun Piao <piaojun@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/ocfs2/journal.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
--- a/fs/ocfs2/journal.c~ocfs2-fix-null-ptr-deref-when-journal-load-failed
+++ a/fs/ocfs2/journal.c
@@ -1055,7 +1055,7 @@ void ocfs2_journal_shutdown(struct ocfs2
if (!igrab(inode))
BUG();
- num_running_trans = atomic_read(&(osb->journal->j_num_trans));
+ num_running_trans = atomic_read(&(journal->j_num_trans));
trace_ocfs2_journal_shutdown(num_running_trans);
/* Do a commit_cache here. It will flush our journal, *and*
@@ -1074,9 +1074,10 @@ void ocfs2_journal_shutdown(struct ocfs2
osb->commit_task = NULL;
}
- BUG_ON(atomic_read(&(osb->journal->j_num_trans)) != 0);
+ BUG_ON(atomic_read(&(journal->j_num_trans)) != 0);
- if (ocfs2_mount_local(osb)) {
+ if (ocfs2_mount_local(osb) &&
+ (journal->j_journal->j_flags & JBD2_LOADED)) {
jbd2_journal_lock_updates(journal->j_journal);
status = jbd2_journal_flush(journal->j_journal, 0);
jbd2_journal_unlock_updates(journal->j_journal);
_
Patches currently in -mm which might be from sunjunchao2870@xxxxxxxxx are
ocfs2-fix-null-ptr-deref-when-journal-load-failed.patch
