snapshot: Reset err to NULL to avoid double free

If an error occurs in bdrv_snapshot_delete_by_id_or_name(), "err" is
freed.  If "err" is not set to NULL before calling
bdrv_snapshot_delete_by_id_or_name() again, it will not be updated on
error, and will be freed again.

This can be triggered by starting a VM with at least two drives and then
attempting to delete a non-existent snapshot.

Broken in commit a89d89d.

Signed-off-by: Chris Spiegel <chris.spiegel@cypherpath.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-id: 1412613225-32676-1-git-send-email-chris.spiegel@cypherpath.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Chris Spiegel 2014-10-06 09:33:45 -07:00 committed by Stefan Hajnoczi
parent 54a7f8f38d
commit ba2b22888c

View file

@ -1246,7 +1246,7 @@ int load_vmstate(const char *name)
void do_delvm(Monitor *mon, const QDict *qdict)
{
BlockDriverState *bs;
Error *err = NULL;
Error *err;
const char *name = qdict_get_str(qdict, "name");
if (!find_vmstate_bs()) {
@ -1257,6 +1257,7 @@ void do_delvm(Monitor *mon, const QDict *qdict)
bs = NULL;
while ((bs = bdrv_next(bs))) {
if (bdrv_can_snapshot(bs)) {
err = NULL;
bdrv_snapshot_delete_by_id_or_name(bs, name, &err);
if (err) {
monitor_printf(mon,