gnome-shell crashed with SIGSEGV in meta_init()

gnome-shell, X11, Radeon R7, Gallium 0.4 on AMD BONAIRE

ProblemType: Crash
DistroRelease: Ubuntu 15.10
Package: gnome-shell 3.16.3-1ubuntu2+wily1 [origin: LP-PPA-gnome3-team-gnome3-staging]
ProcVersionSignature: Ubuntu 4.1.0-2.2-generic 4.1.3
Uname: Linux 4.1.0-2-generic x86_64
ApportVersion: 2.18-0ubuntu2
Architecture: amd64
CurrentDesktop: GNOME
Date: Fri Jul 24 17:06:34 2015
DisplayManager: gdm
ExecutablePath: /usr/bin/gnome-shell
GsettingsChanges:

InstallationDate: Installed on 2015-07-15 (8 days ago)
InstallationMedia: Ubuntu-GNOME 15.10 "Wily Werewolf" - Alpha amd64 (20150714)
ProcCmdline: gnome-shell --mode=gdm
SegvAnalysis:
 Segfault happened at: 0x7f7e63c59ca2: mov 0x14(%rax),%edx
 PC (0x7f7e63c59ca2) ok
 source "0x14(%rax)" (0x00000014) not located in a known VMA region (needed readable region)!
 destination "%edx" ok
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: gnome-shell
StacktraceTop:
 ?? () from /usr/lib/libmutter.so.0
 ?? () from /usr/lib/libmutter.so.0
 meta_init () from /usr/lib/libmutter.so.0
 main ()
Title: gnome-shell crashed with SIGSEGV in meta_init()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: