linux-kernel - Re: [PATCH] drm/gma500: fix double free of gma

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Message-ID: <20201005135227.GQ438822@phenom.ffwll.local>
Date:   Mon, 5 Oct 2020 15:52:27 +0200
From:   Daniel Vetter <daniel@...ll.ch>
To:     trix@...hat.com
Cc:     patrik.r.jakobsson@...il.com, airlied@...ux.ie, daniel@...ll.ch,
        natechancellor@...il.com, ndesaulniers@...gle.com,
        alan@...ux.intel.com, airlied@...hat.com, yakui.zhao@...el.com,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        clang-built-linux@...glegroups.com
Subject: Re: [PATCH] drm/gma500: fix double free of gma_connector

On Sat, Oct 03, 2020 at 12:39:28PM -0700, trix@...hat.com wrote:
> From: Tom Rix <trix@...hat.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@...hat.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