Initialize the structure to 0 so that it's fields won't have random values. For example fields like rec.traffic_class (as well as rec.flow_label and rec.sl) is used to generate the user AH through: cma_iboe_join_multicast cma_make_mc_event ib_init_ah_from_mcmember And a random traffic_class causes a random IP DSCP in RoCEv2. Fixes: b5de0c60cc30 ("RDMA/cma: Fix use after free race in roce multicast join") Signed-off-by: Mark Zhang <markzhang@xxxxxxxxxx> --- Changelog: v1: * Initialize the ib_sa_multicast structure instead of the rec.traffic_class field only v0: https://lore.kernel.org/all/20230926072541.564177-1-markzhang@xxxxxxxxxx/ --- drivers/infiniband/core/cma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c index c343edf2f664..1e2cd7c8716e 100644 --- a/drivers/infiniband/core/cma.c +++ b/drivers/infiniband/core/cma.c @@ -4968,7 +4968,7 @@ static int cma_iboe_join_multicast(struct rdma_id_private *id_priv, int err = 0; struct sockaddr *addr = (struct sockaddr *)&mc->addr; struct net_device *ndev = NULL; - struct ib_sa_multicast ib; + struct ib_sa_multicast ib = {}; enum ib_gid_type gid_type; bool send_only; -- 2.37.1