linux-kernel - Re: [PATCH v3] drm/gma500: fix double freeing

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Date:	Wed, 9 Dec 2015 17:23:04 +0530
From:	Sudip Mukherjee <sudipm.mukherjee@...il.com>
To:	David Airlie <airlied@...ux.ie>,
	Daniel Vetter <daniel.vetter@...ll.ch>,
	patrik.r.jakobsson@...il.com
Cc:	linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH v3] drm/gma500: fix double freeing

On Thu, Oct 08, 2015 at 06:17:48PM +0530, Sudip Mukherjee wrote:
> We are allocating backing using psbfb_alloc() and so
> backing->stolen is always true. So we were freeing backing two times.
> Moreover if we follow the execution path then we should be freeing
> backing after we have released the helper. So remove the one which frees
> backing before the helper is released.
> While at it the error labels are also renamed to give a meaningful
> name.
> 
> Signed-off-by: Sudip Mukherjee <sudip@...torindia.org>
> Reviewed-by: Patrik Jakobsson <patrik.r.jakobsson@...il.com>
> ---

This patch was never picked up. It will not apply now.

Daniel, please let me know if you want me to resend after making
necessary changes.

regards
sudip

>  drivers/gpu/drm/gma500/framebuffer.c | 13 ++++---------
>  1 file changed, 4 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/gma500/framebuffer.c b/drivers/gpu/drm/gma500/framebuffer.c
> index 2eaf1b3..52e2bf3 100644
> --- a/drivers/gpu/drm/gma500/framebuffer.c
> +++ b/drivers/gpu/drm/gma500/framebuffer.c
> @@ -411,7 +411,7 @@ static int psbfb_create(struct psb_fbdev *fbdev,
>  	info = drm_fb_helper_alloc_fbi(&fbdev->psb_fb_helper);
>  	if (IS_ERR(info)) {
>  		ret = PTR_ERR(info);
> -		goto out_err1;
> +		goto err_unlock;
>  	}
>  	info->par = fbdev;
>  
> @@ -419,7 +419,7 @@ static int psbfb_create(struct psb_fbdev *fbdev,
>  
>  	ret = psb_framebuffer_init(dev, psbfb, &mode_cmd, backing);
>  	if (ret)
> -		goto out_unref;
> +		goto err_release;
>  
>  	fb = &psbfb->base;
>  	psbfb->fbdev = info;
> @@ -465,14 +465,9 @@ static int psbfb_create(struct psb_fbdev *fbdev,
>  
>  	mutex_unlock(&dev->struct_mutex);
>  	return 0;
> -out_unref:
> -	if (backing->stolen)
> -		psb_gtt_free_range(dev, backing);
> -	else
> -		drm_gem_object_unreference(&backing->gem);
> -
> +err_release:
>  	drm_fb_helper_release_fbi(&fbdev->psb_fb_helper);
> -out_err1:
> +err_unlock:
>  	mutex_unlock(&dev->struct_mutex);
>  	psb_gtt_free_range(dev, backing);
>  	return ret;
> -- 
> 1.9.1
> 
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