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[v2] drm/gma500: fix double freeing

Message ID 1444146539-5698-1-git-send-email-sudipm.mukherjee@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Sudip Mukherjee Oct. 6, 2015, 3:48 p.m. UTC
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.

Cc: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
---

Hi Patrik,
If you donot like the labels I will change them according to what you
have suggested.   

 drivers/gpu/drm/gma500/framebuffer.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

Comments

Patrik Jakobsson Oct. 7, 2015, 8:55 p.m. UTC | #1
On Tue, Oct 6, 2015 at 5:48 PM, Sudip Mukherjee
<sudipm.mukherjee@gmail.com> 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.
>
> Cc: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
> Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
> ---
>
> Hi Patrik,
> If you donot like the labels I will change them according to what you
> have suggested.

Hi

Label names are used in all sorts of funny ways in the kernel. However
CodingStyle is quite clear on the matter: "Also don't name them after
the goto location like "err_kmalloc_failed:" and if you think about
it, it makes sense. Let's say we add another goto to that label then
the name wouldn't be correct anymore.

err_release and err_unlock would make me happier :)

With that fixed
Reviewed-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>

Thanks

>  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_alloc_fbi;
>         }
>         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_framebuffer_init;
>
>         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_framebuffer_init:
>         drm_fb_helper_release_fbi(&fbdev->psb_fb_helper);
> -out_err1:
> +err_alloc_fbi:
>         mutex_unlock(&dev->struct_mutex);
>         psb_gtt_free_range(dev, backing);
>         return ret;
> --
> 1.9.1
>
diff mbox

Patch

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_alloc_fbi;
 	}
 	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_framebuffer_init;
 
 	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_framebuffer_init:
 	drm_fb_helper_release_fbi(&fbdev->psb_fb_helper);
-out_err1:
+err_alloc_fbi:
 	mutex_unlock(&dev->struct_mutex);
 	psb_gtt_free_range(dev, backing);
 	return ret;