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

BugLink: http://bugs.launchpad.net/bugs/1794889
[ Upstream commit 789d4c300e10eb2096ee83c3497118e67ccc951e ]

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>
Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/drivers/gpu/drm/msm/msm_fbdev.c b/drivers/gpu/drm/msm/msm_fbdev.c
index c178563fcd4dc56a2d1fbdaf4197c847b5c11904..456622b4633558b7d0d98a1d57729aac9d33c57f 100644 (file)
--- 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;
 }