On 07/14/2015 02:20 PM, Thierry Reding wrote:
On Mon, Jul 13, 2015 at 12:08:08PM +0530, Archit Taneja wrote:
[...]
diff --git a/drivers/gpu/drm/tegra/fb.c b/drivers/gpu/drm/tegra/fb.c
[...]
@@ -224,11 +224,11 @@ static int tegra_fbdev_probe(struct drm_fb_helper *helper,
if (IS_ERR(bo))
return PTR_ERR(bo);
- info = framebuffer_alloc(0, drm->dev);
- if (!info) {
+ info = drm_fb_helper_alloc_fbi(helper);
+ if (IS_ERR(info)) {
dev_err(drm->dev, "failed to allocate framebuffer info\n");
- drm_gem_object_unreference_unlocked(&bo->gem);
- return -ENOMEM;
+ err = PTR_ERR(info);
+ goto gem_unref;
}
fbdev->fb = tegra_fb_alloc(drm, &cmd, &bo, 1);
@@ -236,7 +236,6 @@ static int tegra_fbdev_probe(struct drm_fb_helper *helper,
err = PTR_ERR(fbdev->fb);
dev_err(drm->dev, "failed to allocate DRM framebuffer: %d\n",
err);
- drm_gem_object_unreference_unlocked(&bo->gem);
goto release;
}
@@ -248,12 +247,6 @@ static int tegra_fbdev_probe(struct drm_fb_helper *helper,
info->flags = FBINFO_FLAG_DEFAULT;
info->fbops = &tegra_fb_ops;
- err = fb_alloc_cmap(&info->cmap, 256, 0);
- if (err < 0) {
- dev_err(drm->dev, "failed to allocate color map: %d\n", err);
- goto destroy;
- }
-
drm_fb_helper_fill_fix(info, fb->pitches[0], fb->depth);
drm_fb_helper_fill_var(info, helper, fb->width, fb->height);
@@ -282,7 +275,9 @@ destroy:
drm_framebuffer_unregister_private(fb);
tegra_fb_destroy(fb);
release:
- framebuffer_release(info);
+ drm_fb_helper_release_fbi(helper);
+gem_unref:
+ drm_gem_object_unreference_unlocked(&bo->gem);
You can't do this. tegra_fb_alloc() takes ownership of the buffer, so
unless you compensate for that (by taking an explicit reference to the
buffer in tegra_fb_alloc()) you'd be dereferencing twice and likely end
up with use-after-free errors later on.
I'd prefer to keep the error clean up as it is.
Okay. I missed out on the fact that tegra_fb_destroy in the clean up
code calls drm_gem_object_unreference_unlocked. I'll keep it as is.
Archit
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