linux-kernel - [PATCH] mailbox: mailbox-test: set tdev->signal to NULL after freeing

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Message-Id: <1464106324-25005-1-git-send-email-sudeep.holla@arm.com>
Date:	Tue, 24 May 2016 17:12:04 +0100
From:	Sudeep Holla <sudeep.holla@....com>
To:	Lee Jones <lee.jones@...aro.org>,
	Jassi Brar <jaswinder.singh@...aro.org>
Cc:	linux-kernel@...r.kernel.org, Sudeep Holla <sudeep.holla@....com>,
	Jassi Brar <jassisinghbrar@...il.com>
Subject: [PATCH] mailbox: mailbox-test: set tdev->signal to NULL after freeing

tdev->signal is not set NULL after it's freed. This will cause random
exceptions when the stale pointer is accessed after tdev->signal is
freed. Also, since tdev->signal allocation is skipped the next time
it's written, this leads to continuous fault finally leading to the
total death of the system.

Cc: Lee Jones <lee.jones@...aro.org>
Cc: Jassi Brar <jassisinghbrar@...il.com>
Fixes: d1c2f87c9a8f ("mailbox: mailbox-test: Prevent memory leak")
Signed-off-by: Sudeep Holla <sudeep.holla@....com>
---
 drivers/mailbox/mailbox-test.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/mailbox/mailbox-test.c b/drivers/mailbox/mailbox-test.c
index 58d04726cdd7..9ca96e9db6bf 100644
--- a/drivers/mailbox/mailbox-test.c
+++ b/drivers/mailbox/mailbox-test.c
@@ -133,6 +133,7 @@ static ssize_t mbox_test_message_write(struct file *filp,
 out:
 	kfree(tdev->signal);
 	kfree(tdev->message);
+	tdev->signal = NULL;

 	return ret < 0 ? ret : count;
 }
--
1.9.1