[PATCH] drm/radeon: deal with errors from framebuffer init path.

[Dave Airlie]

From: Dave Airlie <airl...@redhat.com>

We've been seeing a very occasional oops on a 32-bit rn50 platform running EL6
kernels at boot. It seems to be due to one of these functions failing and
us then accessing a NULL-300 pointer.

This should prevent the oops and give some info in the logs as to what is going 
on.

Signed-off-by: Dave Airlie <airlied at redhat.com>
---
 drivers/gpu/drm/radeon/radeon_display.c |   18 +++++++++++++++---
 drivers/gpu/drm/radeon/radeon_fb.c      |   11 ++++++++++-
 drivers/gpu/drm/radeon/radeon_mode.h    |    2 +-
 3 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_display.c 
b/drivers/gpu/drm/radeon/radeon_display.c
index 8c49fef..3d31433 100644
--- a/drivers/gpu/drm/radeon/radeon_display.c
+++ b/drivers/gpu/drm/radeon/radeon_display.c
@@ -1078,15 +1078,21 @@ static const struct drm_framebuffer_funcs 
radeon_fb_funcs = {
        .create_handle = radeon_user_framebuffer_create_handle,
 };

-void
+int
 radeon_framebuffer_init(struct drm_device *dev,
                        struct radeon_framebuffer *rfb,
                        struct drm_mode_fb_cmd2 *mode_cmd,
                        struct drm_gem_object *obj)
 {
+       int ret;
        rfb->obj = obj;
-       drm_framebuffer_init(dev, &rfb->base, &radeon_fb_funcs);
+       ret = drm_framebuffer_init(dev, &rfb->base, &radeon_fb_funcs);
+       if (ret) {
+               rfb->obj = NULL;
+               return ret;
+       }
        drm_helper_mode_fill_fb_struct(&rfb->base, mode_cmd);
+       return 0;
 }

 static struct drm_framebuffer *
@@ -1096,6 +1102,7 @@ radeon_user_framebuffer_create(struct drm_device *dev,
 {
        struct drm_gem_object *obj;
        struct radeon_framebuffer *radeon_fb;
+       int ret;

        obj = drm_gem_object_lookup(dev, file_priv, mode_cmd->handles[0]);
        if (obj ==  NULL) {
@@ -1108,7 +1115,12 @@ radeon_user_framebuffer_create(struct drm_device *dev,
        if (radeon_fb == NULL)
                return ERR_PTR(-ENOMEM);

-       radeon_framebuffer_init(dev, radeon_fb, mode_cmd, obj);
+       ret = radeon_framebuffer_init(dev, radeon_fb, mode_cmd, obj);
+       if (ret) {
+               kfree(radeon_fb);
+               drm_gem_object_unreference_unlocked(obj);
+               return NULL;
+       }

        return &radeon_fb->base;
 }
diff --git a/drivers/gpu/drm/radeon/radeon_fb.c 
b/drivers/gpu/drm/radeon/radeon_fb.c
index cf2bf35..195471c 100644
--- a/drivers/gpu/drm/radeon/radeon_fb.c
+++ b/drivers/gpu/drm/radeon/radeon_fb.c
@@ -209,6 +209,11 @@ static int radeonfb_create(struct radeon_fbdev *rfbdev,
                                                          sizes->surface_depth);

        ret = radeonfb_create_pinned_object(rfbdev, &mode_cmd, &gobj);
+       if (ret) {
+               DRM_ERROR("failed to create fbcon object %d\n", ret);
+               return ret;
+       }
+
        rbo = gem_to_radeon_bo(gobj);

        /* okay we have an object now allocate the framebuffer */
@@ -220,7 +225,11 @@ static int radeonfb_create(struct radeon_fbdev *rfbdev,

        info->par = rfbdev;

-       radeon_framebuffer_init(rdev->ddev, &rfbdev->rfb, &mode_cmd, gobj);
+       ret = radeon_framebuffer_init(rdev->ddev, &rfbdev->rfb, &mode_cmd, 
gobj);
+       if (ret) {
+               DRM_ERROR("failed to initalise framebuffer %d\n", ret);
+               goto out_unref;
+       }

        fb = &rfbdev->rfb.base;

diff --git a/drivers/gpu/drm/radeon/radeon_mode.h 
b/drivers/gpu/drm/radeon/radeon_mode.h
index 4330e32..8a85598 100644
--- a/drivers/gpu/drm/radeon/radeon_mode.h
+++ b/drivers/gpu/drm/radeon/radeon_mode.h
@@ -649,7 +649,7 @@ extern void radeon_crtc_fb_gamma_set(struct drm_crtc *crtc, 
u16 red, u16 green,
                                     u16 blue, int regno);
 extern void radeon_crtc_fb_gamma_get(struct drm_crtc *crtc, u16 *red, u16 
*green,
                                     u16 *blue, int regno);
-void radeon_framebuffer_init(struct drm_device *dev,
+int radeon_framebuffer_init(struct drm_device *dev,
                             struct radeon_framebuffer *rfb,
                             struct drm_mode_fb_cmd2 *mode_cmd,
                             struct drm_gem_object *obj);
-- 
1.7.7.6