[patch added to 3.12-stable] Drivers: hv: don't leak memory in vmbus_establish_gpadl()

[Jiri Slaby <jslaby@suse.cz>]

From: Vitaly Kuznetsov <vkuznets@redhat.com>

This patch has been added to the 3.12 stable tree. If you have any
objections, please let us know.

===============

commit 7cc80c98070ccc7940fc28811c92cca0a681015d upstream.

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

[sumits] Note for stable:
Upstream commit 4d63763296ab7865a98bc29cc7d77145815ef89f:
(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: Jiri Slaby <jslaby@suse.cz>
---
 drivers/hv/channel.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index 120237a90a86..8cddbd10dadb 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -403,7 +403,7 @@ 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;
@@ -465,6 +465,13 @@ cleanup:
 	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;
 }
-- 
2.12.2