[PATCH 4/4] intel, gma500, lvds: Fix use after free and mem leak in psb_intel_lvds_init()

Alan Cox alan at lxorguk.ukuu.org.uk
Thu Feb 2 07:19:13 PST 2012

From: Jesper Juhl <jj at chaosbits.net>

In psb_intel_lvds_init(), if we fail to allocate memory for
'psb_intel_connector' we free the memory we previously allocated for
'psb_intel_encoder', but we then proceed to use that free'd pointer
when we do 'psb_intel_encoder->dev_priv = lvds_priv;'.

We may also leak the memory we allocated for 'psb_intel_encoder' if we
'goto failed_connector;' and the variable goes out of scope.

While I was there anyway, I also removed the pointless 'if
(psb_intel_connector)' before freeing it at the 'failed_connector:'
label - kfree() deals gracefully with NULL pointers, so it is not

Signed-off-by: Jesper Juhl <jj at chaosbits.net>
Signed-off-by: Alan Cox <alan at linux.intel.com>

 drivers/gpu/drm/gma500/psb_intel_lvds.c |    9 ++++-----
 1 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/gma500/psb_intel_lvds.c b/drivers/gpu/drm/gma500/psb_intel_lvds.c
index 69a9651..c83f5b5 100644
--- a/drivers/gpu/drm/gma500/psb_intel_lvds.c
+++ b/drivers/gpu/drm/gma500/psb_intel_lvds.c
@@ -713,7 +713,6 @@ void psb_intel_lvds_init(struct drm_device *dev,
 	psb_intel_encoder =
 			kzalloc(sizeof(struct psb_intel_encoder), GFP_KERNEL);
 	if (!psb_intel_encoder) {
 		dev_err(dev->dev, "psb_intel_encoder allocation error\n");
@@ -721,10 +720,9 @@ void psb_intel_lvds_init(struct drm_device *dev,
 	psb_intel_connector =
 		kzalloc(sizeof(struct psb_intel_connector), GFP_KERNEL);
 	if (!psb_intel_connector) {
-		kfree(psb_intel_encoder);
 		dev_err(dev->dev, "psb_intel_connector allocation error\n");
+		goto failed_encoder;
 	lvds_priv = kzalloc(sizeof(struct psb_intel_lvds_priv), GFP_KERNEL);
@@ -862,7 +860,8 @@ failed_blc_i2c:
-	if (psb_intel_connector)
-		kfree(psb_intel_connector);
+	kfree(psb_intel_connector);
+	kfree(psb_intel_encoder);

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