I've found a reproducible segfault when binding a framebuffer. It crashes in the last call in this apitrace for me:
http://constexpr.org/tmp/shadows.trace (105 KiB)
I wouldn't be surprised if this contains invalid calls (nothing detected by Mesa though), but it still shouldn't crash. Haven't tried this on any other drivers yet.
GPU: AMD R9 380X
Mesa 11.3.0-devel (git-750c38f)
#0 driver_RenderTexture_is_safe (att=att@entry=0xb33570)
#1 0x00007ffff29aabc3 in check_begin_texture_render (fb=0xb33300, ctx=0xa9fdb0)
#2 _mesa_bind_framebuffers (ctx=0xa9fdb0, newDrawFb=0xb33300, newReadFb=0xb33300)
#3 0x00000000005773f6 in retrace_glBindFramebuffer (call=...)
Looks like the fix has been pushed, thanks.