linux-kernel - [PATCH 4.9 81/88] Drivers: hv: vmbus: Dont leak memory when a channel is rescinded

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Date:   Tue, 28 Mar 2017 14:31:36 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, "K. Y. Srinivasan" <kys@...rosoft.com>,
        Dexuan Cui <decui@...rosoft.com>
Subject: [PATCH 4.9 81/88] Drivers: hv: vmbus: Dont leak memory when a channel is rescinded

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: K. Y. Srinivasan <kys@...rosoft.com>

commit 5e030d5ce9d99a899b648413139ff65bab12b038 upstream.

When we close a channel that has been rescinded, we will leak memory since
vmbus_teardown_gpadl() returns an error. Fix this so that we can properly
cleanup the memory allocated to the ring buffers.

Fixes: ccb61f8a99e6 ("Drivers: hv: vmbus: Fix a rescind handling bug")

Signed-off-by: K. Y. Srinivasan <kys@...rosoft.com>
Cc: Dexuan Cui <decui@...rosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/hv/channel.c |   13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -506,12 +506,15 @@ int vmbus_teardown_gpadl(struct vmbus_ch
 
 	wait_for_completion(&info->waitevent);
 
-	if (channel->rescind) {
-		ret = -ENODEV;
-		goto post_msg_err;
-	}
-
 post_msg_err:
+	/*
+	 * If the channel has been rescinded;
+	 * we will be awakened by the rescind
+	 * handler; set the error code to zero so we don't leak memory.
+	 */
+	if (channel->rescind)
+		ret = 0;
+
 	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
 	list_del(&info->msglistentry);
 	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags);