From 435d5d7f3a0dd62dc1465c314e338f159fb7d43a Mon Sep 17 00:00:00 2001 From: Thomas Hellstrom Date: Mon, 14 Sep 2015 01:13:11 -0700 Subject: drm/vmwgfx: Fix up user_dmabuf refcounting commit 54c12bc374408faddbff75dbf1a6167c19af39c4 upstream. If user space calls unreference on a user_dmabuf it will typically kill the struct ttm_base_object member which is responsible for the user-space visibility. However the dmabuf part may still be alive and refcounted. In some situations, like for shared guest-backed surface referencing/opening, the driver may try to reference the struct ttm_base_object member again, causing an immediate kernel warning and a later kernel NULL pointer dereference. Fix this by always maintaining a reference on the struct ttm_base_object member, in situations where it might subsequently be referenced. Signed-off-by: Thomas Hellstrom Reviewed-by: Brian Paul Reviewed-by: Sinclair Yeh Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c') diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c b/drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c index 87e39f68e9d0..e1898982b44a 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_overlay.c @@ -484,7 +484,7 @@ int vmw_overlay_ioctl(struct drm_device *dev, void *data, goto out_unlock; } - ret = vmw_user_dmabuf_lookup(tfile, arg->handle, &buf); + ret = vmw_user_dmabuf_lookup(tfile, arg->handle, &buf, NULL); if (ret) goto out_unlock; -- cgit v1.2.3