From 91aa11fae1cf8c2fd67be0609692ea9741cdcc43 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Mon, 12 Aug 2013 09:53:28 -0400 Subject: jbd2: Fix use after free after error in jbd2_journal_dirty_metadata() When jbd2_journal_dirty_metadata() returns error, __ext4_handle_dirty_metadata() stops the handle. However callers of this function do not count with that fact and still happily used now freed handle. This use after free can result in various issues but very likely we oops soon. The motivation of adding __ext4_journal_stop() into __ext4_handle_dirty_metadata() in commit 9ea7a0df seems to be only to improve error reporting. So replace __ext4_journal_stop() with ext4_journal_abort_handle() which was there before that commit and add WARN_ON_ONCE() to dump stack to provide useful information. Reported-by: Sage Weil Signed-off-by: Jan Kara Signed-off-by: "Theodore Ts'o" Cc: stable@vger.kernel.org # 3.2+ --- fs/ext4/ext4_jbd2.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'fs') diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c index 72a3600aedb..17ac112ab10 100644 --- a/fs/ext4/ext4_jbd2.c +++ b/fs/ext4/ext4_jbd2.c @@ -255,10 +255,10 @@ int __ext4_handle_dirty_metadata(const char *where, unsigned int line, set_buffer_prio(bh); if (ext4_handle_valid(handle)) { err = jbd2_journal_dirty_metadata(handle, bh); - if (err) { - /* Errors can only happen if there is a bug */ - handle->h_err = err; - __ext4_journal_stop(where, line, handle); + /* Errors can only happen if there is a bug */ + if (WARN_ON_ONCE(err)) { + ext4_journal_abort_handle(where, line, __func__, bh, + handle, err); } } else { if (inode) -- cgit v1.2.3-70-g09d2