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authorAlan Cox <alan@linux.intel.com>2012-08-20 14:44:52 (GMT)
committerDave Airlie <airlied@redhat.com>2012-08-21 23:26:50 (GMT)
commitf5869a8308f77e3dfdc2e3640842b285aa788ff8 (patch)
tree5595d976c072e81bbd6dda20131841511b5ad79f /drivers/gpu
parent85119c16b34526b2b3c33b01ac6d770aa4431434 (diff)
downloadlinux-f5869a8308f77e3dfdc2e3640842b285aa788ff8.tar.xz
drm: stop vmgfx driver explosion
If you do a page flip with no flags set then event is NULL. If event is NULL then the vmw_gfx driver likes to go digging into NULL and extracts NULL->base.file_priv. On a modern kernel with NULL mapping protection it's just another oops, without it there are some "intriguing" possibilities. What it should do is an open question but that for the driver owners to sort out. Signed-off-by: Alan Cox <alan@linux.intel.com> Reviewed-by: Jakob Bornecrantz <jakob@vmware.com> Cc: stable@vger.kernel.org Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'drivers/gpu')
-rw-r--r--drivers/gpu/drm/vmwgfx/vmwgfx_kms.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
index 6b0078f..c50724b 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
@@ -1688,15 +1688,19 @@ int vmw_du_page_flip(struct drm_crtc *crtc,
struct vmw_private *dev_priv = vmw_priv(crtc->dev);
struct drm_framebuffer *old_fb = crtc->fb;
struct vmw_framebuffer *vfb = vmw_framebuffer_to_vfb(fb);
- struct drm_file *file_priv = event->base.file_priv;
+ struct drm_file *file_priv ;
struct vmw_fence_obj *fence = NULL;
struct drm_clip_rect clips;
int ret;
+ if (event == NULL)
+ return -EINVAL;
+
/* require ScreenObject support for page flipping */
if (!dev_priv->sou_priv)
return -ENOSYS;
+ file_priv = event->base.file_priv;
if (!vmw_kms_screen_object_flippable(dev_priv, crtc))
return -EINVAL;