4.2-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Lukas Czerner <lczer...@redhat.com>

commit 6934da9238da947628be83635e365df41064b09b upstream.

There is a use-after-free possibility in __ext4_journal_stop() in the
case that we free the handle in the first jbd2_journal_stop() because
we're referencing handle->h_err afterwards. This was introduced in
9705acd63b125dee8b15c705216d7186daea4625 and it is wrong. Fix it by
storing the handle->h_err value beforehand and avoid referencing
potentially freed handle.

Fixes: 9705acd63b125dee8b15c705216d7186daea4625
Signed-off-by: Lukas Czerner <lczer...@redhat.com>
Reviewed-by: Andreas Dilger <adil...@dilger.ca>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 fs/ext4/ext4_jbd2.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/fs/ext4/ext4_jbd2.c
+++ b/fs/ext4/ext4_jbd2.c
@@ -88,13 +88,13 @@ int __ext4_journal_stop(const char *wher
                return 0;
        }
 
+       err = handle->h_err;
        if (!handle->h_transaction) {
-               err = jbd2_journal_stop(handle);
-               return handle->h_err ? handle->h_err : err;
+               rc = jbd2_journal_stop(handle);
+               return err ? err : rc;
        }
 
        sb = handle->h_transaction->t_journal->j_private;
-       err = handle->h_err;
        rc = jbd2_journal_stop(handle);
 
        if (!err)


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