From: Xiubo Li <xiubli@xxxxxxxxxx> [ Upstream commit 51884d153f7ec85e18d607b2467820a90e0f4359 ] 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 Link: https://tracker.ceph.com/issues/57686 Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx> Reviewed-by: Ilya Dryomov <idryomov@xxxxxxxxx> Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- fs/ceph/snap.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c index f2731f9efc31..97ce1bd13bad 100644 --- a/fs/ceph/snap.c +++ b/fs/ceph/snap.c @@ -694,7 +694,7 @@ int ceph_update_snap_trace(struct ceph_mds_client *mdsc, struct ceph_mds_snap_realm *ri; /* encoded */ __le64 *snaps; /* encoded */ __le64 *prior_parent_snaps; /* encoded */ - struct ceph_snap_realm *realm = NULL; + struct ceph_snap_realm *realm; struct ceph_snap_realm *first_realm = NULL; struct ceph_snap_realm *realm_to_rebuild = NULL; int rebuild_snapcs; @@ -705,6 +705,7 @@ int ceph_update_snap_trace(struct ceph_mds_client *mdsc, dout("update_snap_trace deletion=%d\n", deletion); more: + realm = NULL; rebuild_snapcs = 0; ceph_decode_need(&p, e, sizeof(*ri), bad); ri = p; -- 2.35.1
