[PATCH] intel, gma500, lvds: Fix use after free on psb_intel_lvds_init()

[Jesper Juhl <jj@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;'.

I believe the proper way to handle this is to simply return after the
allocation for 'psb_intel_connector' has failed. That is what this
patch does.

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
needed.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
---
 drivers/gpu/drm/gma500/psb_intel_lvds.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

 I considered adding a new label at the end and use a goto instead, but
 settled on this minimal solution. If consolidating all exits from the 
 function is prefered then I can rework the patch to do that
 instead. Just let me know.

 Patch is compile tested only since I don't have the hardware to
 actually test it properly.

diff --git a/drivers/gpu/drm/gma500/psb_intel_lvds.c b/drivers/gpu/drm/gma500/psb_intel_lvds.c
index a25e4ca..7d23ef9 100644
--- a/drivers/gpu/drm/gma500/psb_intel_lvds.c
+++ b/drivers/gpu/drm/gma500/psb_intel_lvds.c
@@ -725,6 +725,7 @@ void psb_intel_lvds_init(struct drm_device *dev,
 	if (!psb_intel_connector) {
 		kfree(psb_intel_encoder);
 		dev_err(dev->dev, "psb_intel_connector allocation error\n");
+		return;
 	}
 
 	lvds_priv = kzalloc(sizeof(struct psb_intel_lvds_priv), GFP_KERNEL);
@@ -862,7 +863,6 @@ failed_blc_i2c:
 	drm_encoder_cleanup(encoder);
 	drm_connector_cleanup(connector);
 failed_connector:
-	if (psb_intel_connector)
-		kfree(psb_intel_connector);
+	kfree(psb_intel_connector);
 }
 
-- 
1.7.8.3


-- 
Jesper Juhl <jj@chaosbits.net>       http://www.chaosbits.net/
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