[PATCH] drm/msm: don't deref error pointer in the msm_fbdev_create error path

[PATCH] drm/msm: don't deref error pointer in the msm_fbdev_create error path

[Emil Velikov]

From: Emil Velikov <emil.velikov@collabora.com>

Currently the error pointer returned by msm_alloc_stolen_fb gets passed
to drm_framebuffer_remove. The latter handles only NULL pointers, thus
a nasty crash will occur.

Drop the unnecessary fail label and the associated checks - both err and
fb will be set at this stage.

Cc: Rob Clark <robdclark@gmail.com>
Cc: linux-arm-msm@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: freedreno@lists.freedesktop.org
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
---
 drivers/gpu/drm/msm/msm_fbdev.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_fbdev.c b/drivers/gpu/drm/msm/msm_fbdev.c
index c178563fcd4d..6ed89bcfedf5 100644
--- a/drivers/gpu/drm/msm/msm_fbdev.c
+++ b/drivers/gpu/drm/msm/msm_fbdev.c
@@ -92,8 +92,7 @@ static int msm_fbdev_create(struct drm_fb_helper *helper,
 
 	if (IS_ERR(fb)) {
 		dev_err(dev->dev, "failed to allocate fb\n");
-		ret = PTR_ERR(fb);
-		goto fail;
+		return PTR_ERR(fb);
 	}
 
 	bo = msm_framebuffer_bo(fb, 0);
@@ -153,11 +152,7 @@ static int msm_fbdev_create(struct drm_fb_helper *helper,
 	mutex_unlock(&dev->struct_mutex);
 fail:
 
-	if (ret) {
-		if (fb)
-			drm_framebuffer_remove(fb);
-	}
-
+	drm_framebuffer_remove(fb);
 	return ret;
 }
 
-- 
2.16.0

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[PATCH v2] drm/msm: don't deref error pointer in the msm_fbdev_create error path

[Emil Velikov]

From: Emil Velikov <emil.velikov@collabora.com>

Currently the error pointer returned by msm_alloc_stolen_fb gets passed
to drm_framebuffer_remove. The latter handles only NULL pointers, thus
a nasty crash will occur.

Drop the unnecessary fail label and the associated checks - both err and
fb will be set at this stage.

Cc: Rob Clark <robdclark@gmail.com>
Cc: linux-arm-msm@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: freedreno@lists.freedesktop.org
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
---
v2: really remove the fail label :-\
---
 drivers/gpu/drm/msm/msm_fbdev.c | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_fbdev.c b/drivers/gpu/drm/msm/msm_fbdev.c
index c178563fcd4d..456622b46335 100644
--- a/drivers/gpu/drm/msm/msm_fbdev.c
+++ b/drivers/gpu/drm/msm/msm_fbdev.c
@@ -92,8 +92,7 @@ static int msm_fbdev_create(struct drm_fb_helper *helper,
 
 	if (IS_ERR(fb)) {
 		dev_err(dev->dev, "failed to allocate fb\n");
-		ret = PTR_ERR(fb);
-		goto fail;
+		return PTR_ERR(fb);
 	}
 
 	bo = msm_framebuffer_bo(fb, 0);
@@ -151,13 +150,7 @@ static int msm_fbdev_create(struct drm_fb_helper *helper,
 
 fail_unlock:
 	mutex_unlock(&dev->struct_mutex);
-fail:
-
-	if (ret) {
-		if (fb)
-			drm_framebuffer_remove(fb);
-	}
-
+	drm_framebuffer_remove(fb);
 	return ret;
 }
 
-- 
2.16.0

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Re: [PATCH v2] drm/msm: don't deref error pointer in the msm_fbdev_create error path

[Emil Velikov]

On 28 March 2018 at 17:22, Emil Velikov <emil.l.velikov@gmail.com> wrote:
> From: Emil Velikov <emil.velikov@collabora.com>
>
> Currently the error pointer returned by msm_alloc_stolen_fb gets passed
> to drm_framebuffer_remove. The latter handles only NULL pointers, thus
> a nasty crash will occur.
>
> Drop the unnecessary fail label and the associated checks - both err and
> fb will be set at this stage.
>
> Cc: Rob Clark <robdclark@gmail.com>
> Cc: linux-arm-msm@vger.kernel.org
> Cc: dri-devel@lists.freedesktop.org
> Cc: freedreno@lists.freedesktop.org
> Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
> ---
> v2: really remove the fail label :-\
> ---

Humble ping?

-Emil
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