Mesa (master): glx: guard swap-interval functions against destroyed drawables

[Nicolai Hähnle]

Module: Mesa
Branch: master
Commit: f446f3fb33528eebe9b120340fca3ac5c5ba518d
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=f446f3fb33528eebe9b120340fca3ac5c5ba518d

Author: Nicolai Hähnle <nicolai.haehnle at amd.com>
Date:   Thu Feb  2 18:06:27 2017 +0100

glx: guard swap-interval functions against destroyed drawables

The GLX specification says about glXDestroyPixmap:

    "The storage for the GLX pixmap will be freed when it is not current
     to any client."

So arguably, functions like glXSwapIntervalMESA can be called after
glXDestroyPixmap has been called for the currently bound GLXPixmap.
In that case, the GLXDRIDrawable no longer exists, and so we just skip
those calls.

Cc: 17.0 <mesa-stable at lists.freedesktop.org>
Reviewed-by: Marek Olšák <marek.olsak at amd.com>
Reviewed-by: Emil Velikov <emil.velikov at collabora.com>

---

 src/glx/dri3_glx.c |  4 ++++
 src/glx/glxcmds.c  | 18 +++++++++++++++---
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/src/glx/dri3_glx.c b/src/glx/dri3_glx.c
index 2d40f0a..42a94f9 100644
--- a/src/glx/dri3_glx.c
+++ b/src/glx/dri3_glx.c
@@ -564,6 +564,8 @@ dri3_destroy_screen(struct glx_screen *base)
 static int
 dri3_set_swap_interval(__GLXDRIdrawable *pdraw, int interval)
 {
+   assert(pdraw != NULL);
+
    struct dri3_drawable *priv =  (struct dri3_drawable *) pdraw;
    GLint vblank_mode = DRI_CONF_VBLANK_DEF_INTERVAL_1;
    struct dri3_screen *psc = (struct dri3_screen *) priv->base.psc;
@@ -597,6 +599,8 @@ dri3_set_swap_interval(__GLXDRIdrawable *pdraw, int interval)
 static int
 dri3_get_swap_interval(__GLXDRIdrawable *pdraw)
 {
+   assert(pdraw != NULL);
+
    struct dri3_drawable *priv =  (struct dri3_drawable *) pdraw;
 
   return priv->swap_interval;
diff --git a/src/glx/glxcmds.c b/src/glx/glxcmds.c
index 6c7bbfd..53c9f9c 100644
--- a/src/glx/glxcmds.c
+++ b/src/glx/glxcmds.c
@@ -1761,7 +1761,11 @@ __glXSwapIntervalSGI(int interval)
           psc->driScreen->setSwapInterval) {
       __GLXDRIdrawable *pdraw =
 	 GetGLXDRIDrawable(gc->currentDpy, gc->currentDrawable);
-      psc->driScreen->setSwapInterval(pdraw, interval);
+      /* Simply ignore the command if the GLX drawable has been destroyed but
+       * the context is still bound.
+       */
+      if (pdraw)
+         psc->driScreen->setSwapInterval(pdraw, interval);
       return 0;
    }
 #endif
@@ -1807,7 +1811,14 @@ __glXSwapIntervalMESA(unsigned int interval)
       if (psc && psc->driScreen && psc->driScreen->setSwapInterval) {
          __GLXDRIdrawable *pdraw =
 	    GetGLXDRIDrawable(gc->currentDpy, gc->currentDrawable);
-	 return psc->driScreen->setSwapInterval(pdraw, interval);
+
+         /* Simply ignore the command if the GLX drawable has been destroyed but
+          * the context is still bound.
+          */
+         if (!pdraw)
+            return 0;
+
+         return psc->driScreen->setSwapInterval(pdraw, interval);
       }
    }
 #endif
@@ -1829,7 +1840,8 @@ __glXGetSwapIntervalMESA(void)
       if (psc && psc->driScreen && psc->driScreen->getSwapInterval) {
          __GLXDRIdrawable *pdraw =
 	    GetGLXDRIDrawable(gc->currentDpy, gc->currentDrawable);
-	 return psc->driScreen->getSwapInterval(pdraw);
+         if (pdraw)
+            return psc->driScreen->getSwapInterval(pdraw);
       }
    }
 #endif