[PATCH] drm/gma500: fix double free of gma_connector

[PATCH] drm/gma500: fix double free of gma_connector

[trix]

From: Tom Rix <trix@redhat.com>

clang static analysis reports this problem:

cdv_intel_dp.c:2101:2: warning: Attempt to free released memory
        kfree(gma_connector);
        ^~~~~~~~~~~~~~~~~~~~

In cdv_intel_dp_init() when the call to cdv_intel_edp_panel_vdd_off()
fails, the handler calls cdv_intel_dp_destroy(connector) which does
the first free of gma_connector. So adjust the goto label and skip
the second free.

Fixes: d112a8163f83 ("gma500/cdv: Add eDP support")
Signed-off-by: Tom Rix <trix@redhat.com>
---
 drivers/gpu/drm/gma500/cdv_intel_dp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/gma500/cdv_intel_dp.c b/drivers/gpu/drm/gma500/cdv_intel_dp.c
index 720a767118c9..deb4fd13591d 100644
--- a/drivers/gpu/drm/gma500/cdv_intel_dp.c
+++ b/drivers/gpu/drm/gma500/cdv_intel_dp.c
@@ -2083,7 +2083,7 @@ cdv_intel_dp_init(struct drm_device *dev, struct psb_intel_mode_device *mode_dev
 			DRM_INFO("failed to retrieve link info, disabling eDP\n");
 			drm_encoder_cleanup(encoder);
 			cdv_intel_dp_destroy(connector);
-			goto err_priv;
+			goto err_connector;
 		} else {
         		DRM_DEBUG_KMS("DPCD: Rev=%x LN_Rate=%x LN_CNT=%x LN_DOWNSP=%x\n",
 				intel_dp->dpcd[0], intel_dp->dpcd[1], 
-- 
2.18.1

Re: [PATCH] drm/gma500: fix double free of gma_connector

[Daniel Vetter]

On Sat, Oct 03, 2020 at 12:39:28PM -0700, trix@redhat.com wrote:
> From: Tom Rix <trix@redhat.com>
> 
> clang static analysis reports this problem:
> 
> cdv_intel_dp.c:2101:2: warning: Attempt to free released memory
>         kfree(gma_connector);
>         ^~~~~~~~~~~~~~~~~~~~
> 
> In cdv_intel_dp_init() when the call to cdv_intel_edp_panel_vdd_off()
> fails, the handler calls cdv_intel_dp_destroy(connector) which does
> the first free of gma_connector. So adjust the goto label and skip
> the second free.
> 
> Fixes: d112a8163f83 ("gma500/cdv: Add eDP support")
> Signed-off-by: Tom Rix <trix@redhat.com>

Thanks for your patch, queued in drm-misc-next for 5.11.
-Daniel

> ---
>  drivers/gpu/drm/gma500/cdv_intel_dp.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/gma500/cdv_intel_dp.c b/drivers/gpu/drm/gma500/cdv_intel_dp.c
> index 720a767118c9..deb4fd13591d 100644
> --- a/drivers/gpu/drm/gma500/cdv_intel_dp.c
> +++ b/drivers/gpu/drm/gma500/cdv_intel_dp.c
> @@ -2083,7 +2083,7 @@ cdv_intel_dp_init(struct drm_device *dev, struct psb_intel_mode_device *mode_dev
>  			DRM_INFO("failed to retrieve link info, disabling eDP\n");
>  			drm_encoder_cleanup(encoder);
>  			cdv_intel_dp_destroy(connector);
> -			goto err_priv;
> +			goto err_connector;
>  		} else {
>          		DRM_DEBUG_KMS("DPCD: Rev=%x LN_Rate=%x LN_CNT=%x LN_DOWNSP=%x\n",
>  				intel_dp->dpcd[0], intel_dp->dpcd[1], 
> -- 
> 2.18.1
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch