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From: Mirsad Todorovac
Subject: Test results gpc-20060325 on gcc-4.1.1 P.S.
Date: 14 Feb 2007, 16:06:26

On Wed, 14 Feb 2007, Waldek Hebisch wrote:

> Mirsad Todorovac wrote:
>
>> BUT THE GOOD NEWS is that there are no longer "Killed" error messages, so
>> I think we've found the murderer: it was Linux's PAX kernel extension!
>>
>> chpax has following options, so you will see why it could have affected
>> nonlocal gotos:
>>
>>    -E    emulate trampolines
>>    -e    do not emulate trampolines
>>    -M    restrict mprotect()
>>    -m    do not restrict mprotect()
>
> I wrote previously about nonlocal gotos.  But now I think that the
> problem is with trampolines (problems with nonlocal gotos and trampolines
> are frequently related).  Description of PAX extension makes clear
> that by default trampolines do not work if the extension is active,
> and the affected tests use trampolines.  On other (non-Linux) platforms
> the compiler emits 'mprotect' calls to allows trampolines to work
> (on Linux trampolines are supposed to work even without 'mprotect' call).
> So, the best solution would be to modify gcc so that  'mprotect' gets
> called and to tell PAX to respect 'mprotect' calls.

This means using /sbin/chpax ...

>> This far we have located fault on PAX process killer, so I think the
>> further work is the question whether to allow post-processing command to
>> be executed in test_run script in a general manner, so chpax could be
>> safely executed whenever $PC is.
>>
>
> Some time ago I modified test_run script to allow a runner program: instead
> of running test directly we would call runner program giving it the
> name of executable and the argument list.  This was needed for testing
> cross-compilers (so that runner could launch apropriate emulator), in
> particular I used this to test djgpp and mingw ports (using dosemu and
> wine).  I could probably dig out (or recreate) the patch, but I am
> not sure if such change is worth including in the standard version.

... which would IMHO make a runner program very useful in standard 
distribution. I hope to see it included soon, so we avoid duplicating of 
work.

Regards,
Mirsad

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