[PATCH rdma-next] RDMA/qedr: Fix null-pointer dereference when calling rdma_user_mmap_get_offset

[PATCH rdma-next] RDMA/qedr: Fix null-pointer dereference when calling rdma_user_mmap_get_offset

[Michal Kalderon]

When running against rdma-core that doesn't support doorbell
recovery, the rdma_user_mmap_entry won't be allocated for
doorbell recovery related mappings.
We have a flag indicating whether rdma-core supports doorbell
recovery or not which was used during initialization, however
some cases didn't check that the rdma_user_mmap_entry exists
before attempting to acquire it's offset.

Fixes: 97f612509294 ("RDMA/qedr: Add doorbell overflow recovery support")
Signed-off-by: Ariel Elior <ariel.elior@marvell.com>
Signed-off-by: Michal Kalderon <michal.kalderon@marvell.com>
---
 drivers/infiniband/hw/qedr/verbs.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/infiniband/hw/qedr/verbs.c b/drivers/infiniband/hw/qedr/verbs.c
index 9c0887c61f72..3f3f0ef2f901 100644
--- a/drivers/infiniband/hw/qedr/verbs.c
+++ b/drivers/infiniband/hw/qedr/verbs.c
@@ -697,7 +697,9 @@ static int qedr_copy_cq_uresp(struct qedr_dev *dev,
 
 	uresp.db_offset = db_offset;
 	uresp.icid = cq->icid;
-	uresp.db_rec_addr = rdma_user_mmap_get_offset(cq->q.db_mmap_entry);
+	if (cq->q.db_mmap_entry)
+		uresp.db_rec_addr =
+			rdma_user_mmap_get_offset(cq->q.db_mmap_entry);
 
 	rc = qedr_ib_copy_to_udata(udata, &uresp, sizeof(uresp));
 	if (rc)
@@ -1026,7 +1028,7 @@ int qedr_create_cq(struct ib_cq *ibcq, const struct ib_cq_init_attr *attr,
 	if (udata) {
 		qedr_free_pbl(dev, &cq->q.pbl_info, cq->q.pbl_tbl);
 		ib_umem_release(cq->q.umem);
-		if (ctx)
+		if (cq->q.db_mmap_entry)
 			rdma_user_mmap_entry_remove(cq->q.db_mmap_entry);
 	} else {
 		dev->ops->common->chain_free(dev->cdev, &cq->pbl);
@@ -1259,7 +1261,9 @@ static void qedr_copy_rq_uresp(struct qedr_dev *dev,
 	}
 
 	uresp->rq_icid = qp->icid;
-	uresp->rq_db_rec_addr = rdma_user_mmap_get_offset(qp->urq.db_mmap_entry);
+	if (qp->urq.db_mmap_entry)
+		uresp->rq_db_rec_addr =
+			rdma_user_mmap_get_offset(qp->urq.db_mmap_entry);
 }
 
 static void qedr_copy_sq_uresp(struct qedr_dev *dev,
@@ -1274,8 +1278,9 @@ static void qedr_copy_sq_uresp(struct qedr_dev *dev,
 	else
 		uresp->sq_icid = qp->icid + 1;
 
-	uresp->sq_db_rec_addr =
-		rdma_user_mmap_get_offset(qp->usq.db_mmap_entry);
+	if (qp->usq.db_mmap_entry)
+		uresp->sq_db_rec_addr =
+			rdma_user_mmap_get_offset(qp->usq.db_mmap_entry);
 }
 
 static int qedr_copy_qp_uresp(struct qedr_dev *dev,
-- 
2.20.1

Re: [PATCH rdma-next] RDMA/qedr: Fix null-pointer dereference when calling rdma_user_mmap_get_offset

[Jason Gunthorpe]

On Mon, Nov 18, 2019 at 05:06:45PM +0200, Michal Kalderon wrote:
> When running against rdma-core that doesn't support doorbell
> recovery, the rdma_user_mmap_entry won't be allocated for
> doorbell recovery related mappings.
> We have a flag indicating whether rdma-core supports doorbell
> recovery or not which was used during initialization, however
> some cases didn't check that the rdma_user_mmap_entry exists
> before attempting to acquire it's offset.
> 
> Fixes: 97f612509294 ("RDMA/qedr: Add doorbell overflow recovery support")
> Signed-off-by: Ariel Elior <ariel.elior@marvell.com>
> Signed-off-by: Michal Kalderon <michal.kalderon@marvell.com>
> ---
>  drivers/infiniband/hw/qedr/verbs.c | 15 ++++++++++-----
>  1 file changed, 10 insertions(+), 5 deletions(-)

Applied to for-next, thanks

Jason