[PATCH 5.19 119/717] jbd2: fix potential buffer head reference count leak

Greg Kroah-Hartman
2022-10-22T08:18:03Z

From: Ye Bin <yebin10@huawei.com>

commit e0d5fc7a6d80ac2406c7dfc6bb625201d0250a8a upstream.

As in 'jbd2_fc_wait_bufs' if buffer isn't uptodate, will return -EIO without
update 'journal->j_fc_off'. But 'jbd2_fc_release_bufs' will release buffer head
from ‘j_fc_off - 1’ if 'bh' is NULL will terminal release which will lead to
buffer head buffer head reference count leak.
To solve above issue, update 'journal->j_fc_off' before return -EIO.

Cc: stable@kernel.org
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220914100812.1414768-2-yebin10@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/jbd2/journal.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -928,8 +928,14 @@ int jbd2_fc_wait_bufs(journal_t *journal
wait_on_buffer(bh);
put_bh(bh);
journal->j_fc_wbuf[i] = NULL;
- if (unlikely(!buffer_uptodate(bh)))
+ /*
+ * Update j_fc_off so jbd2_fc_release_bufs can release remain
+ * buffer head.
+ */
+ if (unlikely(!buffer_uptodate(bh))) {
+ journal->j_fc_off = i;
return -EIO;
+ }
}

return 0;