WebGL shader running on Intel Mesa causes machine freeze

[0152la]

[Shaders, screenshots, error log, reproduction steps, platform info, etc.] [ZIP]

Trying to render the variant shader in Chrome leads to a number of observable issues:

• the browser seemingly hangs indefinitely (have left it for more than 10 minutes)
• the browser hangs for a varied amount of time (up to two minutes), after which it recovers successfully with a lot of information being emitted in the terminal
• the entire machine freezes, with no apparent remedy except a hard reset

We have managed to reproduce the machine freeze consistently, via the "run_kill.sh" script, which launches the browser, rendering the shader after a short while. After a set timeout, the script kills the browser, and relaunches it. It does this up to a given number of times. In our experiments, the second time it attempts to render the shader, the machine consistently freezes.

Interestingly, the issue does not present itself on Firefox. In that case, the browser hangs for a short time (a matter of seconds), after which the individual tab crashes.

[0152la]

Reported to Mesa at https://bugs.freedesktop.org/show_bug.cgi?id=100231