This is a note to let you know that I've just added the patch titled RDMA/mlx5: Fix potential race between destroy and CQE poll to the 5.8-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: rdma-mlx5-fix-potential-race-between-destroy-and-cqe.patch and it can be found in the queue-5.8 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 94efd6eb940f3265383544f95f3dbe62c90873b2 Author: Leon Romanovsky <leon@xxxxxxxxxx> Date: Sun Aug 30 11:40:04 2020 +0300 RDMA/mlx5: Fix potential race between destroy and CQE poll [ Upstream commit 4b916ed9f9e85f705213ca8d69771d3c1cd6ee5a ] The SRQ can be destroyed right before mlx5_cmd_get_srq is called. In such case the latter will return NULL instead of expected SRQ. Fixes: e126ba97dba9 ("mlx5: Add driver for Mellanox Connect-IB adapters") Link: https://lore.kernel.org/r/20200830084010.102381-5-leon@xxxxxxxxxx Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxxxx> Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/infiniband/hw/mlx5/cq.c b/drivers/infiniband/hw/mlx5/cq.c index 0c18cb6a2f148..3ca379513d0e6 100644 --- a/drivers/infiniband/hw/mlx5/cq.c +++ b/drivers/infiniband/hw/mlx5/cq.c @@ -168,7 +168,7 @@ static void handle_responder(struct ib_wc *wc, struct mlx5_cqe64 *cqe, { enum rdma_link_layer ll = rdma_port_get_link_layer(qp->ibqp.device, 1); struct mlx5_ib_dev *dev = to_mdev(qp->ibqp.device); - struct mlx5_ib_srq *srq; + struct mlx5_ib_srq *srq = NULL; struct mlx5_ib_wq *wq; u16 wqe_ctr; u8 roce_packet_type; @@ -180,7 +180,8 @@ static void handle_responder(struct ib_wc *wc, struct mlx5_cqe64 *cqe, if (qp->ibqp.xrcd) { msrq = mlx5_cmd_get_srq(dev, be32_to_cpu(cqe->srqn)); - srq = to_mibsrq(msrq); + if (msrq) + srq = to_mibsrq(msrq); } else { srq = to_msrq(qp->ibqp.srq); }