[PATCH v2] drm/gma500: fix double freeing

[PATCH v2] drm/gma500: fix double freeing

[Sudip Mukherjee]

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(-)

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

Re: [PATCH v2] drm/gma500: fix double freeing

[Patrik Jakobsson]

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
>

[PATCH v3] drm/gma500: fix double freeing

[Sudip Mukherjee]

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@vectorindia.org>
Reviewed-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
---
 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

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

[Sudip Mukherjee]

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@vectorindia.org>
> Reviewed-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.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
> 

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

[Patrik Jakobsson]

On Wed, Dec 9, 2015 at 12:53 PM, Sudip Mukherjee
<sudipm.mukherjee@gmail.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@vectorindia.org>
>> Reviewed-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.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
>>

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

[Sudip Mukherjee]

On Wednesday 09 December 2015 05:50 PM, Patrik Jakobsson wrote:
> On Wed, Dec 9, 2015 at 12:53 PM, Sudip Mukherjee
> <sudipm.mukherjee@gmail.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@vectorindia.org>
>>> Reviewed-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.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
>>>

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

[Patrik Jakobsson]

On Thu, Apr 7, 2016 at 5:52 PM, Sudip Mukherjee
<sudipm.mukherjee@gmail.com> wrote:
> On Wednesday 09 December 2015 05:50 PM, Patrik Jakobsson wrote:
>>
>> On Wed, Dec 9, 2015 at 12:53 PM, Sudip Mukherjee
>> <sudipm.mukherjee@gmail.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@vectorindia.org>
>>>> Reviewed-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.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..

I already have it rebased, will send it out later tonight. For real this time ;)

Thanks
Patrik

>
> 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
>>>>
>