Comment 21 for bug 1492037

I can reproduce it here on ArchLinux with broadwell. Googling a bit shows it happening for people using xbmc, gnome shell or plasma on various distros.

I just hacked in a null check to stop the crashing for now (hard to work when the desktop shell keeps crashing):

diff --git a/src/mesa/drivers/dri/i965/brw_meta_fast_clear.c b/src/mesa/drivers/dri/i965/brw_meta_fast_clear.c
index 5b8191c..f0e5e77 100644
--- a/src/mesa/drivers/dri/i965/brw_meta_fast_clear.c
+++ b/src/mesa/drivers/dri/i965/brw_meta_fast_clear.c
@@ -442,6 +442,10 @@ brw_meta_fast_clear(struct brw_context *brw, struct gl_framebuffer *fb,
       if (rb == NULL)
          continue;

+ // For some reason this render buffer can lack a mipmap tree
+ if (irb->mt == NULL)
+ continue;
+
       clear_type = FAST_CLEAR;

       /* We don't have fast clear until gen7. */