From: Xiubo Li <xiubli@xxxxxxxxxx> When decoding the snaps fails it maybe leaving the 'first_realm' and 'realm' pointing to the same snaprealm memory. And then it'll put it twice and could cause random use-after-free, BUG_ON, etc issues. Cc: stable@xxxxxxxxxxxxxxx URL: https://tracker.ceph.com/issues/57686 Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx> --- fs/ceph/snap.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c index 9bceed2ebda3..baf17df05107 100644 --- a/fs/ceph/snap.c +++ b/fs/ceph/snap.c @@ -849,10 +849,12 @@ int ceph_update_snap_trace(struct ceph_mds_client *mdsc, if (realm_to_rebuild && p >= e) rebuild_snap_realms(realm_to_rebuild, &dirty_realms); - if (!first_realm) + if (!first_realm) { first_realm = realm; - else + realm = NULL; + } else { ceph_put_snap_realm(mdsc, realm); + } if (p < e) goto more; -- 2.31.1
