Drivers: hv: don't leak memory in vmbus_establish_gpadl()

commit 7cc80c98 upstream.

In some cases create_gpadl_header() allocates submessages but we never
free them.

[sumits] Note for stable:
Upstream commit 4d637632:
(Drivers: hv: get rid of redundant messagecount in create_gpadl_header())
changes the list usage to initialize list header in all cases; that patch
isn't added to stable, so the current patch is modified a little bit from
the upstream commit to check if the list is valid or not.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

drivers/hv/channel.c

@@ -391,7 +391,7 @@ int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
 	struct vmbus_channel_gpadl_header *gpadlmsg;
 	struct vmbus_channel_gpadl_body *gpadl_body;
 	struct vmbus_channel_msginfo *msginfo = NULL;
-	struct vmbus_channel_msginfo *submsginfo;
+	struct vmbus_channel_msginfo *submsginfo, *tmp;
 	u32 msgcount;
 	struct list_head *curr;
 	u32 next_gpadl_handle;
@@ -453,6 +453,13 @@ int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer,
 	list_del(&msginfo->msglistentry);
 	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);
 
+	if (msgcount > 1) {
+		list_for_each_entry_safe(submsginfo, tmp, &msginfo->submsglist,
+			 msglistentry) {
+			kfree(submsginfo);
+		}
+	}
+
 	kfree(msginfo);
 	return ret;
 }