Commit 6e051971 authored by Jason Gunthorpe's avatar Jason Gunthorpe
Browse files

RDMA/siw: Fix potential siw_mem refcnt leak in siw_fastreg_mr() 

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: b9be6f18 ("rdma/siw: transmit path")
Link: https://lore.kernel.org/r/1586939949-69856-1-git-send-email-xiyuyang19@fudan.edu.cn


Reported-by: default avatarXiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
parent c08cfb2d

drivers/infiniband/sw/siw/siw_qp_tx.c

+11 −4
Original line number Diff line number Diff line
@@ -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;