diff mbox series

[4/5] Critical-KlockWork-Fix-intel_tv.c-Possible-Null

Message ID 20200819043409.26010-4-nischal.varide@intel.com (mailing list archive)
State New, archived
Headers show
Series [1/5] Critical-KclockWork-Fixes-intel_atomi.c-PossibleNull | expand

Commit Message

Nischal Varide Aug. 19, 2020, 4:34 a.m. UTC 
This patch fixes the Critical Klock work Error and in this case a
Possible Null Pointer Dereference has been addressed with a Null check
before dereferencing

Signed-off-by: Nischal Varide <nischal.varide@intel.com>
---
 drivers/gpu/drm/i915/display/intel_tv.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

Comments

Gupta, Anshuman Aug. 24, 2020, 6:32 a.m. UTC | #1 
On 2020-08-19 at 10:04:08 +0530, Nischal Varide wrote:
> This patch fixes the Critical Klock work Error and in this case a
> Possible Null Pointer Dereference has been addressed with a Null check
> before dereferencing
> 
> Signed-off-by: Nischal Varide <nischal.varide@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_tv.c | 17 ++++++++++-------
>  1 file changed, 10 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_tv.c b/drivers/gpu/drm/i915/display/intel_tv.c
> index 777032d9697b..5600d146ae81 100644
> --- a/drivers/gpu/drm/i915/display/intel_tv.c
> +++ b/drivers/gpu/drm/i915/display/intel_tv.c
> @@ -1836,17 +1836,20 @@ static int intel_tv_atomic_check(struct drm_connector *connector,
>  	struct drm_connector_state *old_state;
>  
>  	new_state = drm_atomic_get_new_connector_state(state, connector);
> -	if (!new_state->crtc)
> -		return 0;
> -
>  	old_state = drm_atomic_get_old_connector_state(state, connector);
>  	new_crtc_state = drm_atomic_get_new_crtc_state(state, new_state->crtc);
>  
> +	if (!(old_state && new_state && new_crtc_state))
> +		return 0;
> +
> +	if (!new_state->crtc)
> +		return 0;
> +
>  	if (old_state->tv.mode != new_state->tv.mode ||
> -	    old_state->tv.margins.left != new_state->tv.margins.left ||
> -	    old_state->tv.margins.right != new_state->tv.margins.right ||
> -	    old_state->tv.margins.top != new_state->tv.margins.top ||
> -	    old_state->tv.margins.bottom != new_state->tv.margins.bottom) {
> +		old_state->tv.margins.left != new_state->tv.margins.left ||
> +		old_state->tv.margins.right != new_state->tv.margins.right ||
> +		old_state->tv.margins.top != new_state->tv.margins.top ||
> +		old_state->tv.margins.bottom != new_state->tv.margins.bottom) {
This seems unwanted changes.
Thanks,
Anshuman.
>  		/* Force a modeset. */
>  
>  		new_crtc_state->connectors_changed = true;
> -- 
> 2.26.0
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
Dan Carpenter Aug. 25, 2020, 9:31 a.m. UTC | #2 
Hi Nischal,

Thank you for the patch! Perhaps something to improve:

url:    https://github.com/0day-ci/linux/commits/Nischal-Varide/Critical-KclockWork-Fixes-intel_atomi-c-PossibleNull/20200819-193249
base:   git://anongit.freedesktop.org/drm-intel for-linux-next
config: i386-randconfig-m021-20200824 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

smatch warnings:
drivers/gpu/drm/i915/display/intel_tv.c:1842 intel_tv_atomic_check() warn: variable dereferenced before check 'new_state' (see line 1840)

# https://github.com/0day-ci/linux/commit/6fb528c1b424d3c8095085afa7e777ac5502450b
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Nischal-Varide/Critical-KclockWork-Fixes-intel_atomi-c-PossibleNull/20200819-193249
git checkout 6fb528c1b424d3c8095085afa7e777ac5502450b
vim +/new_state +1842 drivers/gpu/drm/i915/display/intel_tv.c

0e891b3f447f4d drivers/gpu/drm/i915/intel_tv.c         Maarten Lankhorst 2017-04-10  1831  static int intel_tv_atomic_check(struct drm_connector *connector,
6f3b62781bbd26 drivers/gpu/drm/i915/intel_tv.c         Sean Paul         2019-06-11  1832  				 struct drm_atomic_state *state)
0e891b3f447f4d drivers/gpu/drm/i915/intel_tv.c         Maarten Lankhorst 2017-04-10  1833  {
6f3b62781bbd26 drivers/gpu/drm/i915/intel_tv.c         Sean Paul         2019-06-11  1834  	struct drm_connector_state *new_state;
0e891b3f447f4d drivers/gpu/drm/i915/intel_tv.c         Maarten Lankhorst 2017-04-10  1835  	struct drm_crtc_state *new_crtc_state;
0e891b3f447f4d drivers/gpu/drm/i915/intel_tv.c         Maarten Lankhorst 2017-04-10  1836  	struct drm_connector_state *old_state;
0e891b3f447f4d drivers/gpu/drm/i915/intel_tv.c         Maarten Lankhorst 2017-04-10  1837  
6f3b62781bbd26 drivers/gpu/drm/i915/intel_tv.c         Sean Paul         2019-06-11  1838  	new_state = drm_atomic_get_new_connector_state(state, connector);
6f3b62781bbd26 drivers/gpu/drm/i915/intel_tv.c         Sean Paul         2019-06-11  1839  	old_state = drm_atomic_get_old_connector_state(state, connector);
6f3b62781bbd26 drivers/gpu/drm/i915/intel_tv.c         Sean Paul         2019-06-11 @1840  	new_crtc_state = drm_atomic_get_new_crtc_state(state, new_state->crtc);
                                                                                                                                                      ^^^^^^^^^^^^^^^
Dereference

0e891b3f447f4d drivers/gpu/drm/i915/intel_tv.c         Maarten Lankhorst 2017-04-10  1841  
6fb528c1b424d3 drivers/gpu/drm/i915/display/intel_tv.c Nischal Varide    2020-08-19 @1842  	if (!(old_state && new_state && new_crtc_state))
                                                                                                                   ^^^^^^^^^
Checked too late

6fb528c1b424d3 drivers/gpu/drm/i915/display/intel_tv.c Nischal Varide    2020-08-19  1843  		return 0;
6fb528c1b424d3 drivers/gpu/drm/i915/display/intel_tv.c Nischal Varide    2020-08-19  1844  
6fb528c1b424d3 drivers/gpu/drm/i915/display/intel_tv.c Nischal Varide    2020-08-19  1845  	if (!new_state->crtc)
6fb528c1b424d3 drivers/gpu/drm/i915/display/intel_tv.c Nischal Varide    2020-08-19  1846  		return 0;
6fb528c1b424d3 drivers/gpu/drm/i915/display/intel_tv.c Nischal Varide    2020-08-19  1847  
0e891b3f447f4d drivers/gpu/drm/i915/intel_tv.c         Maarten Lankhorst 2017-04-10  1848  	if (old_state->tv.mode != new_state->tv.mode ||
0e891b3f447f4d drivers/gpu/drm/i915/intel_tv.c         Maarten Lankhorst 2017-04-10  1849  		old_state->tv.margins.left != new_state->tv.margins.left ||
0e891b3f447f4d drivers/gpu/drm/i915/intel_tv.c         Maarten Lankhorst 2017-04-10  1850  		old_state->tv.margins.right != new_state->tv.margins.right ||
0e891b3f447f4d drivers/gpu/drm/i915/intel_tv.c         Maarten Lankhorst 2017-04-10  1851  		old_state->tv.margins.top != new_state->tv.margins.top ||
0e891b3f447f4d drivers/gpu/drm/i915/intel_tv.c         Maarten Lankhorst 2017-04-10  1852  		old_state->tv.margins.bottom != new_state->tv.margins.bottom) {
0e891b3f447f4d drivers/gpu/drm/i915/intel_tv.c         Maarten Lankhorst 2017-04-10  1853  		/* Force a modeset. */
0e891b3f447f4d drivers/gpu/drm/i915/intel_tv.c         Maarten Lankhorst 2017-04-10  1854  
0e891b3f447f4d drivers/gpu/drm/i915/intel_tv.c         Maarten Lankhorst 2017-04-10  1855  		new_crtc_state->connectors_changed = true;
0e891b3f447f4d drivers/gpu/drm/i915/intel_tv.c         Maarten Lankhorst 2017-04-10  1856  	}
0e891b3f447f4d drivers/gpu/drm/i915/intel_tv.c         Maarten Lankhorst 2017-04-10  1857  
0e891b3f447f4d drivers/gpu/drm/i915/intel_tv.c         Maarten Lankhorst 2017-04-10  1858  	return 0;
0e891b3f447f4d drivers/gpu/drm/i915/intel_tv.c         Maarten Lankhorst 2017-04-10  1859  }

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/display/intel_tv.c b/drivers/gpu/drm/i915/display/intel_tv.c
index 777032d9697b..5600d146ae81 100644
--- a/drivers/gpu/drm/i915/display/intel_tv.c
+++ b/drivers/gpu/drm/i915/display/intel_tv.c
@@ -1836,17 +1836,20 @@  static int intel_tv_atomic_check(struct drm_connector *connector,
 	struct drm_connector_state *old_state;
 
 	new_state = drm_atomic_get_new_connector_state(state, connector);
-	if (!new_state->crtc)
-		return 0;
-
 	old_state = drm_atomic_get_old_connector_state(state, connector);
 	new_crtc_state = drm_atomic_get_new_crtc_state(state, new_state->crtc);
 
+	if (!(old_state && new_state && new_crtc_state))
+		return 0;
+
+	if (!new_state->crtc)
+		return 0;
+
 	if (old_state->tv.mode != new_state->tv.mode ||
-	    old_state->tv.margins.left != new_state->tv.margins.left ||
-	    old_state->tv.margins.right != new_state->tv.margins.right ||
-	    old_state->tv.margins.top != new_state->tv.margins.top ||
-	    old_state->tv.margins.bottom != new_state->tv.margins.bottom) {
+		old_state->tv.margins.left != new_state->tv.margins.left ||
+		old_state->tv.margins.right != new_state->tv.margins.right ||
+		old_state->tv.margins.top != new_state->tv.margins.top ||
+		old_state->tv.margins.bottom != new_state->tv.margins.bottom) {
 		/* Force a modeset. */
 
 		new_crtc_state->connectors_changed = true;