[PATCH] RDMA/irdma: Fix potential NULL-ptr-dereference

[Nikita Zhandarovich]

in_dev_get() can return NULL which will cause a failure once idev is
dereferenced in in_dev_for_each_ifa_rtnl(). This patch adds a
check for NULL value in idev beforehand.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 146b9756f14c ("RDMA/irdma: Add connection manager")
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@xxxxxxxxxx>

 drivers/infiniband/hw/irdma/cm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/infiniband/hw/irdma/cm.c b/drivers/infiniband/hw/irdma/cm.c
index 7b086fe63a24..195aa9ea18b6 100644
--- a/drivers/infiniband/hw/irdma/cm.c
+++ b/drivers/infiniband/hw/irdma/cm.c
@@ -1722,6 +1722,9 @@ static int irdma_add_mqh_4(struct irdma_device *iwdev,
 			continue;
 
 		idev = in_dev_get(ip_dev);
+		if (!idev)
+			continue;
+
 		in_dev_for_each_ifa_rtnl(ifa, idev) {
 			ibdev_dbg(&iwdev->ibdev,
 				  "CM: Allocating child CM Listener forIP=%pI4, vlan_id=%d, MAC=%pM\n",