[PATCH 180/222] RDMA/nes: Fix for crash when registering zero length MR for CQ

[Herton Ronaldo Krzesinski]

3.5.7.3 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tatyana Nikolova <Tatyana.E.Nikolova at intel.com>

commit 7d9c199a55200c9b9fcad08e150470d02fb385be upstream.

Signed-off-by: Tatyana Nikolova <Tatyana.E.Nikolova at intel.com>
Signed-off-by: Roland Dreier <roland at purestorage.com>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>
---
 drivers/infiniband/hw/nes/nes_verbs.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/infiniband/hw/nes/nes_verbs.c b/drivers/infiniband/hw/nes/nes_verbs.c
index 2359568..da84ea3 100644
--- a/drivers/infiniband/hw/nes/nes_verbs.c
+++ b/drivers/infiniband/hw/nes/nes_verbs.c
@@ -2561,6 +2561,11 @@ static struct ib_mr *nes_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 			return ibmr;
 		case IWNES_MEMREG_TYPE_QP:
 		case IWNES_MEMREG_TYPE_CQ:
+			if (!region->length) {
+				nes_debug(NES_DBG_MR, "Unable to register zero length region for CQ\n");
+				ib_umem_release(region);
+				return ERR_PTR(-EINVAL);
+			}
 			nespbl = kzalloc(sizeof(*nespbl), GFP_KERNEL);
 			if (!nespbl) {
 				nes_debug(NES_DBG_MR, "Unable to allocate PBL\n");
-- 
1.7.9.5