IB/sa_query: Check if sm_ah is NULL in ib_sa_remove_one()

If update_sm_ah() fails, it leaves the port's sm_ah as NULL.  Then if
the device or module is removed, ib_sa_remove_one() will dereference a
NULL pointer when it calls kref_put().  Fix this by testing if sm_ah
is NULL before dropping the reference.

Signed-off-by: Ralph Campbell <ralph.campbell@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/infiniband/core/sa_query.c b/drivers/infiniband/core/sa_query.c
index 1341de793e51..7863a50d56f2 100644
--- a/drivers/infiniband/core/sa_query.c
+++ b/drivers/infiniband/core/sa_query.c
@@ -1064,7 +1064,8 @@ static void ib_sa_remove_one(struct ib_device *device)
 
         for (i = 0; i <= sa_dev->end_port - sa_dev->start_port; ++i) {
                 ib_unregister_mad_agent(sa_dev->port[i].agent);
-                kref_put(&sa_dev->port[i].sm_ah->ref, free_sm_ah);
+                if (sa_dev->port[i].sm_ah)
+                        kref_put(&sa_dev->port[i].sm_ah->ref, free_sm_ah);
         }
 
         kfree(sa_dev);