From ed7d78b2da32198ca4c70172e3b63c6b3e2c570b Mon Sep 17 00:00:00 2001 From: Thomas Hellstrom Date: Mon, 12 Oct 2015 01:49:39 -0700 Subject: [PATCH] drm/vmwgfx: Fix kernel NULL pointer dereference on older hardware The commit "drm/vmwgfx: Fix up user_dmabuf refcounting", while fixing a kernel crash introduced a NULL pointer dereference on older hardware. Fix this. Cc: Signed-off-by: Thomas Hellstrom Reviewed-by: Sinclair Yeh Reviewed-by: Brian Paul --- drivers/gpu/drm/vmwgfx/vmwgfx_surface.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c index 64b50409fa07..03f63c749c02 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c @@ -657,7 +657,8 @@ static void vmw_user_surface_base_release(struct ttm_base_object **p_base) struct vmw_resource *res = &user_srf->srf.res; *p_base = NULL; - ttm_base_object_unref(&user_srf->backup_base); + if (user_srf->backup_base) + ttm_base_object_unref(&user_srf->backup_base); vmw_resource_unreference(&res); }