linux-kernel - [PATCH] platform/chrome: Fix locking pattern in wilco_ec

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Message-Id: <20190311155838.255314-1-ncrews@chromium.org>
Date:   Mon, 11 Mar 2019 09:58:38 -0600
From:   Nick Crews <ncrews@...omium.org>
To:     enric.balletbo@...labora.com, bleung@...omium.org
Cc:     linux-kernel@...r.kernel.org, dlaurie@...omium.org,
        groeck@...gle.com, dtor@...gle.com,
        Nick Crews <ncrews@...omium.org>
Subject: [PATCH] platform/chrome: Fix locking pattern in wilco_ec_mailbox()

Before, ec->data_buffer could be written to from multiple
contexts at the same time. Since the ec is shared data,
it needs to be inside the mutex as well.

Signed-off-by: Nick Crews <ncrews@...omium.org>
---
 drivers/platform/chrome/wilco_ec/mailbox.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/chrome/wilco_ec/mailbox.c b/drivers/platform/chrome/wilco_ec/mailbox.c
index f6ff29a11f1a..d6cb96168285 100644
--- a/drivers/platform/chrome/wilco_ec/mailbox.c
+++ b/drivers/platform/chrome/wilco_ec/mailbox.c
@@ -223,12 +223,12 @@ int wilco_ec_mailbox(struct wilco_ec_device *ec, struct wilco_ec_message *msg)
 		msg->command, msg->type, msg->flags, msg->response_size,
 		msg->request_size);
 
-	/* Prepare request packet */
+	mutex_lock(&ec->mailbox_lock);
+
 	rq = ec->data_buffer;
 	wilco_ec_prepare(msg, rq);
-
-	mutex_lock(&ec->mailbox_lock);
 	ret = wilco_ec_transfer(ec, msg, rq);
+	
 	mutex_unlock(&ec->mailbox_lock);
 
 	return ret;
--