egl/android: fix segfault within swap_buffers

Function droid_swap_buffers may get called without dri2_surf->buffer set,
in these cases we don't have a back buffer set either. Patch fixes segfault
seen with 3DMark that uses android.opengl.GLSurfaceView for rendering it's UI.

backtrace:
   #00 pc 00013f88  /system/lib/egl/libGLES_mesa.so (droid_swap_buffers+104)
   #01 pc 000117b2  /system/lib/egl/libGLES_mesa.so (dri2_swap_buffers+50)
   #02 pc 000058b2  /system/lib/egl/libGLES_mesa.so (eglSwapBuffers+386)
   #03 pc 00011329  /system/lib/libEGL.so (eglSwapBuffersWithDamageKHR+553)
   #04 pc 000118e7  /system/lib/libEGL.so (eglSwapBuffers+55)
   #05 pc 000754dc  /system/lib/libandroid_runtime.so

Note, this is v1 as v2 caused dEQP regressions.

Fixes: 2acc69d ("EGL/Android: Add EGL_EXT_buffer_age extension")
Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
Acked-by: Emil Velikov <emil.velikov@collabora.com>
Cc: "17.1" <mesa-stable@lists.freedesktop.org>

diff --git a/src/egl/drivers/dri2/platform_android.c b/src/egl/drivers/dri2/platform_android.c
index 49cbeb4698e265b468942469e923100b92eccf8e..de24a8f5c49ee13c6402e53794e898ff13c7cace 100644 (file)
--- a/src/egl/drivers/dri2/platform_android.c
+++ b/src/egl/drivers/dri2/platform_android.c
@@ -628,7 +628,12 @@ droid_swap_buffers(_EGLDriver *drv, _EGLDisplay *disp, _EGLSurface *draw)
       if (dri2_surf->color_buffers[i].age > 0)
          dri2_surf->color_buffers[i].age++;
    }
-   dri2_surf->back->age = 1;
+
+   /* "XXX: we don't use get_back_bo() since it causes regressions in
+    * several dEQP tests.
+    */
+   if (dri2_surf->back)
+      dri2_surf->back->age = 1;
 
    dri2_flush_drawable_for_swapbuffers(disp, draw);