ShCrOpenGL crashes in 5.1.8(including test build revision 111724) but not in 5.1.6 when activating input method framework in Ubuntu 16.04

[林博仁(Buo-Ren, Lin)]

Reproduce Steps

This isn't too reproduce-friendly as most people doesn't uses IM Frameworks, however it happened to be reproduced on my [Custom Ubuntu VM Virtual Applicance project](​https://github.com/Not-That-Ubuntu-Taiwan-Community/Ubuntu-TW-VM), and I also exported and released an Open Virtualization Archive recently! So you may grab & import the 1.7GB VM and having the pretty much same guest system to reproduce this issue on :). Here's the steps:

1. Import & launch the VM
2. The login screen will require you to manually set a new password by asking twice, then login to the X session.
3. Open the "dash" screen(an UI element in Unity DE, refer: ​https://help.ubuntu.com/stable/ubuntu-help/unity-dash-intro.html )
4. Hold-press-release the Control + Space key conbination

Symptoms

• (Most of the time) VM crashes with "ShCrOpenGL[19586]: segfault at 2d0 ip 00007fc1af685c90 s

p 00007fc16e42a9f8 error 4 in libc-2.23.so[7fc1af5e7000+1bf000]" in system log

• (Very few) VM doesn't crash, however the UI of the IM Framework display abnormally

Other Information

Operating System

Ubuntu 16.04LTS AMD64

Host Graphics

Intel Graphics on a NVIDIA Optimus Laptop(NVIDIA chip not enabled)

Mesa 3D

Stock version from Ubuntu 16.04 archive

Locale

zh_TW.UTF-8

[林博仁(Buo-Ren, Lin)]

UPDATE: The title is wrong as I can reproduce the issue also on 5.1.6, sorry for the confusion.

Symptoms (new)

• It seems that after I switched back to 5.1.6 the crash entry in syslog turns to "ShCrOpenGL[15049]: segfault at 2d0 ip 00007f3b7325bd10 sp 00007f3ba05f49a0 error 4 in i965_dri.so[7f3b730c4000+605000]"

Additional Information

• The host graphics is Intel® HD Graphics 4000 from Intel® Core™ i5-3337U Processor(Ivybridge)
• I failed to acquire the coredump by following the "Creating core dumps to help analyze VirtualBox crashes" guide, there's no .crash file generated in /var/crash after the VM crashed.