st/egl: Fix a crash when unbinding current context.

This fixes a NULL-pointer dereference when
eglMakeCurrent(dpy, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT)
is called.

Signed-off-by: Chia-I Wu <olvaffe@gmail.com>

3 files changed, 4 insertions, 14 deletions

diff --git a/src/gallium/state_trackers/egl/egl_context.c b/src/gallium/state_trackers/egl/egl_context.c
index c4f7361ca0..288186ad72 100644
--- a/src/gallium/state_trackers/egl/egl_context.c
+++ b/src/gallium/state_trackers/egl/egl_context.c
@@ -160,18 +160,12 @@ drm_make_current(_EGLDriver *drv, _EGLDisplay *dpy, _EGLSurface *draw, _EGLSurfa
 		if (!drawSurf || !readSurf)
 			return EGL_FALSE;
 
-		drawSurf->user = ctx;
-		readSurf->user = ctx;
-
 		st_make_current(ctx->st, drawSurf->stfb, readSurf->stfb);
 
 		/* st_resize_framebuffer needs a bound context to work */
 		st_resize_framebuffer(drawSurf->stfb, drawSurf->w, drawSurf->h);
 		st_resize_framebuffer(readSurf->stfb, readSurf->w, readSurf->h);
 	} else {
-		drawSurf->user = NULL;
-		readSurf->user = NULL;
-
 		st_make_current(NULL, NULL, NULL);
 	}
 
diff --git a/src/gallium/state_trackers/egl/egl_surface.c b/src/gallium/state_trackers/egl/egl_surface.c
index 542ac56121..7911a8834e 100644
--- a/src/gallium/state_trackers/egl/egl_surface.c
+++ b/src/gallium/state_trackers/egl/egl_surface.c
@@ -352,24 +352,21 @@ drm_swap_buffers(_EGLDriver *drv, _EGLDisplay *dpy, _EGLSurface *draw)
 	if (!surf)
 		return EGL_FALSE;
 
-	/* error checking */
-	if (!_eglSwapBuffers(drv, dpy, draw))
-		return EGL_FALSE;
-
 	st_get_framebuffer_surface(surf->stfb, ST_SURFACE_BACK_LEFT, &back_surf);
 
 	if (back_surf) {
+		struct drm_context *ctx = lookup_drm_context(draw->Binding);
 
 		st_notify_swapbuffers(surf->stfb);
 
-		if (surf->screen) {
-			surf->user->pipe->surface_copy(surf->user->pipe,
+		if (ctx && surf->screen) {
+			ctx->pipe->surface_copy(ctx->pipe,
 				surf->screen->surface,
 				0, 0,
 				back_surf,
 				0, 0,
 				surf->w, surf->h);
-			surf->user->pipe->flush(surf->user->pipe, PIPE_FLUSH_RENDER_CACHE | PIPE_FLUSH_TEXTURE_CACHE, NULL);
+			ctx->pipe->flush(ctx->pipe, PIPE_FLUSH_RENDER_CACHE | PIPE_FLUSH_TEXTURE_CACHE, NULL);
 
 #ifdef DRM_MODE_FEATURE_DIRTYFB
 			/* TODO query connector property to see if this is needed */
diff --git a/src/gallium/state_trackers/egl/egl_tracker.h b/src/gallium/state_trackers/egl/egl_tracker.h
index f280748d65..73eb1a1226 100644
--- a/src/gallium/state_trackers/egl/egl_tracker.h
+++ b/src/gallium/state_trackers/egl/egl_tracker.h
@@ -69,7 +69,6 @@ struct drm_surface
 	 * drm
 	 */
 
-	struct drm_context *user;
 	struct drm_screen *screen;
 
 	int w;