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

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Message-ID: <5706823B.7060800@gmail.com>
Date:	Thu, 07 Apr 2016 21:22:27 +0530
From:	Sudip Mukherjee <sudipm.mukherjee@...il.com>
To:	Patrik Jakobsson <patrik.r.jakobsson@...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 Wednesday 09 December 2015 05:50 PM, Patrik Jakobsson wrote:
> 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.

This was not picked up. But I guess it is still true. Do you want me to 
rebase and send it again..

regards
sudip

>
> -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
>>>