From: Majd Dibbiny <majd@mellanox.com>
Date: Mon, 19 Aug 2013 15:19:23 +0000 (+0300)
Subject: ib_core: Safely unregister mad agent when necessary.
X-Git-Tag: v4.1.12-92~293^2~1^2~65
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=e6f8aedab6134bdfc736c5f3b535abe50418f3d1;p=users%2Fjedix%2Flinux-maple.git

ib_core: Safely unregister mad agent when necessary.

When the allocation of the receive buffer fails the driver
needs to unregister the mad agent. The function
ib_unregister_mad_agent doesn't check if the pointer of the
mad agent is valid and doesn't contain an error and causes a
Kernel Panic. Therefore, we need to check if the pointer of
the mad agent is valid by calling PTR_ERR and only then
unregister the agent.

Signed-off-by: Majd Dibbiny <majd@mellanox.com>
(Ported from Mellanox OFED 2.4)

Signed-off-by: Mukesh Kacker <mukesh.kacker@oracle.com>
---

diff --git a/drivers/infiniband/core/mad.c b/drivers/infiniband/core/mad.c
index 4b759308ff3df..af878a71ee3fe 100644
--- a/drivers/infiniband/core/mad.c
+++ b/drivers/infiniband/core/mad.c
@@ -619,18 +619,21 @@ int ib_unregister_mad_agent(struct ib_mad_agent *mad_agent)
 	struct ib_mad_agent_private *mad_agent_priv;
 	struct ib_mad_snoop_private *mad_snoop_priv;
 
-	/* If the TID is zero, the agent can only snoop. */
-	if (mad_agent->hi_tid) {
-		mad_agent_priv = container_of(mad_agent,
+	if (!IS_ERR(mad_agent)) {
+		/* If the TID is zero, the agent can only snoop. */
+		if (mad_agent->hi_tid) {
+			mad_agent_priv = container_of(mad_agent,
 					      struct ib_mad_agent_private,
 					      agent);
-		unregister_mad_agent(mad_agent_priv);
-	} else {
-		mad_snoop_priv = container_of(mad_agent,
+			unregister_mad_agent(mad_agent_priv);
+		} else {
+			mad_snoop_priv = container_of(mad_agent,
 					      struct ib_mad_snoop_private,
 					      agent);
-		unregister_mad_snoop(mad_snoop_priv);
+			unregister_mad_snoop(mad_snoop_priv);
+		}
 	}
+
 	return 0;
 }
 EXPORT_SYMBOL(ib_unregister_mad_agent);