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...

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@gmail.com 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@gmail.com Fixes: f6f50e28f0cb ("jbd2: Fail to load a journal if it is too short") Signed-off-by: Julian Sun sunjunchao2870@gmail.com Reported-by: syzbot+05b9b39d8bdfe1a0861f@syzkaller.appspotmail.com Suggested-by: Joseph Qi joseph.qi@linux.alibaba.com Reviewed-by: Joseph Qi joseph.qi@linux.alibaba.com Cc: Mark Fasheh mark@fasheh.com Cc: Joel Becker jlbec@evilplan.org Cc: Junxiao Bi junxiao.bi@oracle.com Cc: Changwei Ge gechangwei@live.cn Cc: Gang He ghe@suse.com Cc: Jun Piao piaojun@huawei.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

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@gmail.com are

ocfs2-fix-null-ptr-deref-when-journal-load-failed.patch