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

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Message-ID: <CAMeQTsaPPh5m1rHtPLYP85N6hVH-KRvcyf+XhP8TrZiqhmDE=w@mail.gmail.com>
Date:	Wed, 9 Dec 2015 13:20:01 +0100
From:	Patrik Jakobsson <patrik.r.jakobsson@...il.com>
To:	Sudip Mukherjee <sudipm.mukherjee@...il.com>
Cc:	David Airlie <airlied@...ux.ie>,
	Daniel Vetter <daniel.vetter@...ll.ch>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	dri-devel <dri-devel@...ts.freedesktop.org>
Subject: Re: [PATCH v3] drm/gma500: fix double freeing

On Wed, Dec 9, 2015 at 12:53 PM, Sudip Mukherjee
<sudipm.mukherjee@...il.com> wrote:
> 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.

I will pick this up and pass it along to Dave. Sorry for the delay.

-Patrik

>
> 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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