On Sun, 8 Jul 2012, Paul Menzel wrote:

Dear Julia,

Am Sonntag, den 08.07.2012, 13:37 +0200 schrieb Julia Lawall:

...

From: Julia Lawall Julia.Lawall@lip6.fr

If list_for_each_entry, etc complete a traversal of the list, the iterator variable ends up pointing to an address at an offset from the list head, and not a meaningful structure. Thus this value should not be used after the end of the iterator.

In the first two cases, a a break is added after the switch; the break in

s,a a,a,

Thanks.

...

the switch would jump out of the switch, but not out of the complete iteration.

In the first case, the null test on connector is removed, because the iterator variable of list_for_each_entry is never null.

In the third case, entry->base.crtc.fb is not a meaningful value. What seems to be intended is crtc->fb, which gets the information from the last element of the list.

maybe three separate patches would have been better?

OK, I wasn't sure what would be best. I'll send three patches now.

...

These problems were found using Coccinelle (http://coccinelle.lip6.fr/).

I always liked your example Coccinelle code snippets. Could you add them again to your commit messages? That would be awesome!

Sure. I didn't include it because there was a 0/7 message that has the complete semantic patch.

julia

...

Signed-off-by: Julia Lawall Julia.Lawall@lip6.fr

---

drivers/gpu/drm/gma500/mdfld_intel_display.c | 4 +--- drivers/gpu/drm/gma500/oaktrail_crtc.c | 1 + drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c | 2 +- 3 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/gma500/mdfld_intel_display.c b/drivers/gpu/drm/gma500/mdfld_intel_display.c index 3f3cd61..fc1ced0 100644 --- a/drivers/gpu/drm/gma500/mdfld_intel_display.c +++ b/drivers/gpu/drm/gma500/mdfld_intel_display.c @@ -755,9 +755,6 @@ static int mdfld_crtc_mode_set(struct drm_crtc *crtc, sizeof(struct drm_display_mode));

list_for_each_entry(connector, &mode_config->connector_list, head) {

• if (!connector)
  

• 	continue;
  

• encoder = connector->encoder;

  if (!encoder)

@@ -779,6 +776,7 @@ static int mdfld_crtc_mode_set(struct drm_crtc *crtc, is_hdmi = true; break; }

• break;
  

  }

  /* Disable the VGA plane that we never use */

diff --git a/drivers/gpu/drm/gma500/oaktrail_crtc.c b/drivers/gpu/drm/gma500/oaktrail_crtc.c index f821c83..4b2172e 100644 --- a/drivers/gpu/drm/gma500/oaktrail_crtc.c +++ b/drivers/gpu/drm/gma500/oaktrail_crtc.c @@ -329,6 +329,7 @@ static int oaktrail_crtc_mode_set(struct drm_crtc *crtc, is_mipi = true; break; }

• break;
  

  }

  /* Disable the VGA plane that we never use */

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c b/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c index 070fb23..634611a 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c @@ -93,7 +93,7 @@ static int vmw_ldu_commit_list(struct vmw_private *dev_priv)

if (crtc == NULL)
	return 0;

• fb = entry->base.crtc.fb;
  

• fb = crtc->fb;
  
  

  return vmw_kms_write_svga(dev_priv, w, h, fb->pitches[0], fb->bits_per_pixel, fb->depth);

Acked-by: Paul Menzel paulepanter@users.sourceforge.net

Thanks,

Paul