[PATCH v3 0/2] Parfait changes

[PATCH v3 0/2] Parfait changes

[Joe Moriarty]

The following patch(s) are bugs found by the static compiler
'Parfait'.  Care was taken to make sure false positive results
were removed from this patchset.

Parfait Overview
================

https://labs.oracle.com/pls/apex/f?p=labs:49:::::P49_PROJECT_ID:13

v1:
Initial release

v2:
- Split original v1 patch into 4 separate patches per request
from Jani Nikula
- Fixed system hang during boot up on test machine.

v3:
- Made changes requested by Daniel Vetter.

Joe Moriarty (2):
  drm: NULL pointer dereference [null-pointer-deref] (CWE 476) problem
  drm: NULL pointer dereference [null-pointer-deref] (CWE 476) problem

 drivers/gpu/drm/drm_drv.c    | 2 +-
 drivers/gpu/drm/drm_vblank.c | 9 +++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

-- 
2.15.0

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[PATCH v3 1/2] drm: NULL pointer dereference [null-pointer-deref] (CWE 476) problem

[Joe Moriarty]

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>
---
 drivers/gpu/drm/drm_vblank.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c
index 32d9bcf5be7f..03b431eb47ae 100644
--- a/drivers/gpu/drm/drm_vblank.c
+++ b/drivers/gpu/drm/drm_vblank.c
@@ -120,6 +120,9 @@ static u32 __get_vblank_counter(struct drm_device *dev, unsigned int pipe)
 	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_device *dev, unsigned int pipe)
 	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;
@@ -918,6 +924,9 @@ static int __enable_vblank(struct drm_device *dev, unsigned int pipe)
 	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);
 	}
-- 
2.15.0

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[PATCH v3 2/2] drm: NULL pointer dereference [null-pointer-deref] (CWE 476) problem

[Joe Moriarty]

The Parfait (version 2.1.0) static code analysis tool found the
following NULL pointer dereference problem.

- drivers/gpu/drm/drm_drv.c
Any calls to drm_minor_get_slot() could result in the return of a NULL
pointer when an invalid DRM device type is encountered.  The
return of NULL was removed with BUG() from drm_minor_get_slot().

Signed-off-by: Joe Moriarty <joe.moriarty@oracle.com>
Reviewed-by: Steven Sistare <steven.sistare@oracle.com>
---
 drivers/gpu/drm/drm_drv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 9acc1e157813..a1b9338736e3 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -99,7 +99,7 @@ static struct drm_minor **drm_minor_get_slot(struct drm_device *dev,
 	case DRM_MINOR_CONTROL:
 		return &dev->control;
 	default:
-		return NULL;
+		BUG();
 	}
 }
 
-- 
2.15.0

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Re: [PATCH v3 0/2] Parfait changes

[Joe Moriarty]

On 2/20/2018 2:11 PM, Joe Moriarty wrote:
> The following patch(s) are bugs found by the static compiler
> 'Parfait'.  Care was taken to make sure false positive results
> were removed from this patchset.
> 
> Parfait Overview
> ================
> 
> https://labs.oracle.com/pls/apex/f?p=labs:49:::::P49_PROJECT_ID:13
> 
> v1:
> Initial release
> 
> v2:
> - Split original v1 patch into 4 separate patches per request
> from Jani Nikula
> - Fixed system hang during boot up on test machine.
> 
> v3:
> - Made changes requested by Daniel Vetter.
> 
> Joe Moriarty (2):
>    drm: NULL pointer dereference [null-pointer-deref] (CWE 476) problem
>    drm: NULL pointer dereference [null-pointer-deref] (CWE 476) problem
> 
>   drivers/gpu/drm/drm_drv.c    | 2 +-
>   drivers/gpu/drm/drm_vblank.c | 9 +++++++++
>   2 files changed, 10 insertions(+), 1 deletion(-)
> 
Ping, Waiting on review/addition of these 2 patches to drm-misc-next.

Thanks,
Joe
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Re: [PATCH v3 0/2] Parfait changes

[Daniel Vetter]

On Mon, Mar 05, 2018 at 11:14:11AM -0500, Joe Moriarty wrote:
> On 2/20/2018 2:11 PM, Joe Moriarty wrote:
> > The following patch(s) are bugs found by the static compiler
> > 'Parfait'.  Care was taken to make sure false positive results
> > were removed from this patchset.
> > 
> > Parfait Overview
> > ================
> > 
> > https://labs.oracle.com/pls/apex/f?p=labs:49:::::P49_PROJECT_ID:13
> > 
> > v1:
> > Initial release
> > 
> > v2:
> > - Split original v1 patch into 4 separate patches per request
> > from Jani Nikula
> > - Fixed system hang during boot up on test machine.
> > 
> > v3:
> > - Made changes requested by Daniel Vetter.
> > 
> > Joe Moriarty (2):
> >    drm: NULL pointer dereference [null-pointer-deref] (CWE 476) problem
> >    drm: NULL pointer dereference [null-pointer-deref] (CWE 476) problem
> > 
> >   drivers/gpu/drm/drm_drv.c    | 2 +-
> >   drivers/gpu/drm/drm_vblank.c | 9 +++++++++
> >   2 files changed, 10 insertions(+), 1 deletion(-)
> > 
> Ping, Waiting on review/addition of these 2 patches to drm-misc-next.

I was on vacation, and I guess no one else cared. Btw, minor process nit:
Including internal review tags is fairly pointless, since generally I have
no idea about how it happened (there's no public record), nor do I know
the experience level of your reviewer. That makes the r-b tag fairly
value-less in this case. If you want to included it's much better to do
that review on the m-l, after submission.

Anyway, thanks for respinning, patches merged.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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