RDMA/iwcm: Don't access a cm_id after dropping reference
cm_work_handler() can access cm_id_priv after it drops its reference
by calling iwch_deref_id(), which might cause it to be freed. The fix
is to look at whether IWCM_F_CALLBACK_DESTROY is set _before_ dropping
the reference. Then if it was set, free the cm_id on this thread.
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/infiniband/core/iwcm.c b/drivers/infiniband/core/iwcm.c
index 223b1aa..81c9195 100644
--- a/drivers/infiniband/core/iwcm.c
+++ b/drivers/infiniband/core/iwcm.c
@@ -839,6 +839,7 @@
unsigned long flags;
int empty;
int ret = 0;
+ int destroy_id;
spin_lock_irqsave(&cm_id_priv->lock, flags);
empty = list_empty(&cm_id_priv->work_list);
@@ -857,9 +858,9 @@
destroy_cm_id(&cm_id_priv->id);
}
BUG_ON(atomic_read(&cm_id_priv->refcount)==0);
+ destroy_id = test_bit(IWCM_F_CALLBACK_DESTROY, &cm_id_priv->flags);
if (iwcm_deref_id(cm_id_priv)) {
- if (test_bit(IWCM_F_CALLBACK_DESTROY,
- &cm_id_priv->flags)) {
+ if (destroy_id) {
BUG_ON(!list_empty(&cm_id_priv->work_list));
free_cm_id(cm_id_priv);
}