From: Joe Moriarty <joe.moriarty@oracle.com>
Date: Tue, 20 Feb 2018 14:11:56 -0500
Subject: drm: NULL pointer dereference [null-pointer-deref] (CWE 476) problem
Git-commit: 4ffb8deeed58b75dd1a23580845233b6ce0dca6c
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166
The Parfait (version 2.1.0) static code analysis tool found the
following NULL pointer derefernce problem.
- drivers/gpu/drm/drm_vblank.c
Null pointer checks were added to return values from calls to
drm_crtc_from_index(). There is a possibility, however minute, that
crtc->index may not be found when trying to find the struct crtc
from it's assigned index given in drm_crtc_init_with_planes().
3 return checks for NULL where added with a call to
WARN_ON(!crtc).
Signed-off-by: Joe Moriarty <joe.moriarty@oracle.com>
Reviewed-by: Steven Sistare <steven.sistare@oracle.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180220191157.100960-2-joe.moriarty@oracle.com
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
drivers/gpu/drm/drm_vblank.c | 9 +++++++++
1 file changed, 9 insertions(+)
--- a/drivers/gpu/drm/drm_vblank.c
+++ b/drivers/gpu/drm/drm_vblank.c
@@ -120,6 +120,9 @@ static u32 __get_vblank_counter(struct d
if (drm_core_check_feature(dev, DRIVER_MODESET)) {
struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
+ if (WARN_ON(!crtc))
+ return 0;
+
if (crtc->funcs->get_vblank_counter)
return crtc->funcs->get_vblank_counter(crtc);
}
@@ -318,6 +321,9 @@ static void __disable_vblank(struct drm_
if (drm_core_check_feature(dev, DRIVER_MODESET)) {
struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
+ if (WARN_ON(!crtc))
+ return;
+
if (crtc->funcs->disable_vblank) {
crtc->funcs->disable_vblank(crtc);
return;
@@ -919,6 +925,9 @@ static int __enable_vblank(struct drm_de
if (drm_core_check_feature(dev, DRIVER_MODESET)) {
struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
+ if (WARN_ON(!crtc))
+ return 0;
+
if (crtc->funcs->enable_vblank)
return crtc->funcs->enable_vblank(crtc);
}