linux-kernel - [PATCH] staging: bcm2835-audio: Fix memory corruption

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Date:   Tue,  8 Aug 2017 13:05:02 +0100
From:   Phil Elwell <phil@...pberrypi.org>
To:     Eric Anholt <eric@...olt.net>,
        Stefan Wahren <stefan.wahren@...e.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Florian Fainelli <f.fainelli@...il.com>,
        Aishwarya Pant <aishpant@...il.com>,
        Dan Carpenter <dan.carpenter@...cle.com>,
        linux-rpi-kernel@...ts.infradead.org, devel@...verdev.osuosl.org,
        linux-kernel@...r.kernel.org
Cc:     Phil Elwell <phil@...pberrypi.org>
Subject: [PATCH] staging: bcm2835-audio: Fix memory corruption

I'm all for fixing memory leaks, but freeing a block while it is still
being used is a recipe for hard-to-debug kernel exceptions.

1) There is already a vchi method for freeing the instance, so use it.
2) Only call it on error, and then only before initted is false.

Signed-off-by: Phil Elwell <phil@...pberrypi.org>
Fixes: 0adbfd4694c2 ("staging: bcm2835-audio: fix memory leak in bcm2835_audio_open_connection()")
---
 drivers/staging/vc04_services/bcm2835-audio/bcm2835-vchiq.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/vc04_services/bcm2835-audio/bcm2835-vchiq.c b/drivers/staging/vc04_services/bcm2835-audio/bcm2835-vchiq.c
index 5f3d8f2..89f96f3 100644
--- a/drivers/staging/vc04_services/bcm2835-audio/bcm2835-vchiq.c
+++ b/drivers/staging/vc04_services/bcm2835-audio/bcm2835-vchiq.c
@@ -409,6 +409,7 @@ static int bcm2835_audio_open_connection(struct bcm2835_alsa_stream *alsa_stream
 			LOG_ERR("%s: failed to connect VCHI instance (ret=%d)\n",
 				__func__, ret);
 
+			vchi_disconnect(vchi_instance);
 			ret = -EIO;
 			goto err_free_mem;
 		}
@@ -431,7 +432,6 @@ static int bcm2835_audio_open_connection(struct bcm2835_alsa_stream *alsa_stream
 	LOG_DBG(" success !\n");
 	ret = 0;
 err_free_mem:
-	kfree(vchi_instance);
 
 	return ret;
 }
-- 
1.9.1