Bug#851263: vbetool: crashes by executing illegal hardware instruction

[Adrian Bunk <bunk@debian.org>]

Control: reassign -1 libx86-1 1.1+ds1-10.1
Control: severity -1 serious
Control: retitle -1 libx86-1: illegal instruction

On Fri, Jan 13, 2017 at 02:32:30PM +0100, Sebastian Humenda wrote:
> Package: vbetool
> Version: 1.1-4
> Severity: normal
> 
> Hi
> 
> Using `dpms off` to switch off the display does not work anymore:
> 
>     % sudo vbetool dpms off
>     zsh: illegal hardware instruction  sudo vbetool dpms off
> 
> I can confirm this on both a 32bit and 64bit system.
>...
> Versions of packages vbetool depends on:
>...
> ii  libx86-1  1.1+ds1-10.1
>...

Thanks for your report.

I can reproduce it, and there are two workarounds I found:
1. downgrade libx86-1 to 1.1+ds1-10 from stable, OR
2. recompile libx86-1 with -O1

This sounds like a bug in libx86-1 that got exposed by better 
optimization in recent gcc.

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed