This is a note to let you know that I've just added the patch titled RDMA/siw: Fix potential siw_mem refcnt leak in siw_fastreg_mr() to the 5.6-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-siw-fix-potential-siw_mem-refcnt-leak-in-siw_fa.patch and it can be found in the queue-5.6 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit c4a21b6a425bba1aeafd8d15482e34752c16077d Author: Jason Gunthorpe <jgg@xxxxxxxxxxxx> Date: Wed Apr 15 11:09:22 2020 -0300 RDMA/siw: Fix potential siw_mem refcnt leak in siw_fastreg_mr() commit 6e051971b0e2eeb0ce7ec65d3cc8180450512d36 upstream. siw_fastreg_mr() invokes siw_mem_id2obj(), which returns a local reference of the siw_mem object to "mem" with increased refcnt. When siw_fastreg_mr() returns, "mem" becomes invalid, so the refcount should be decreased to keep refcount balanced. The issue happens in one error path of siw_fastreg_mr(). When "base_mr" equals to NULL but "mem" is not NULL, the function forgets to decrease the refcnt increased by siw_mem_id2obj() and causes a refcnt leak. Reorganize the flow so that the goto unwind can be used as expected. Fixes: b9be6f18cf9e ("rdma/siw: transmit path") Link: https://lore.kernel.org/r/1586939949-69856-1-git-send-email-xiyuyang19@xxxxxxxxxxxx Reported-by: Xiyu Yang <xiyuyang19@xxxxxxxxxxxx> Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> diff --git a/drivers/infiniband/sw/siw/siw_qp_tx.c b/drivers/infiniband/sw/siw/siw_qp_tx.c index ae92c8080967c..9f53aa4feb878 100644 --- a/drivers/infiniband/sw/siw/siw_qp_tx.c +++ b/drivers/infiniband/sw/siw/siw_qp_tx.c @@ -920,20 +920,27 @@ static int siw_fastreg_mr(struct ib_pd *pd, struct siw_sqe *sqe) { struct ib_mr *base_mr = (struct ib_mr *)(uintptr_t)sqe->base_mr; struct siw_device *sdev = to_siw_dev(pd->device); - struct siw_mem *mem = siw_mem_id2obj(sdev, sqe->rkey >> 8); + struct siw_mem *mem; int rv = 0; siw_dbg_pd(pd, "STag 0x%08x\n", sqe->rkey); - if (unlikely(!mem || !base_mr)) { + if (unlikely(!base_mr)) { pr_warn("siw: fastreg: STag 0x%08x unknown\n", sqe->rkey); return -EINVAL; } + if (unlikely(base_mr->rkey >> 8 != sqe->rkey >> 8)) { pr_warn("siw: fastreg: STag 0x%08x: bad MR\n", sqe->rkey); - rv = -EINVAL; - goto out; + return -EINVAL; } + + mem = siw_mem_id2obj(sdev, sqe->rkey >> 8); + if (unlikely(!mem)) { + pr_warn("siw: fastreg: STag 0x%08x unknown\n", sqe->rkey); + return -EINVAL; + } + if (unlikely(mem->pd != pd)) { pr_warn("siw: fastreg: PD mismatch\n"); rv = -EINVAL;