Re: Segfault on syscall

Shuveb Hussain wrote:
> Hi,
>
>> Well, it's not, but as I said there still is this bug in the syscalls
>> thing, and since this is a 'random'  bug, I need as much full detailed
>> bug report (see the wiki :
>> http://howto.x-tend.be/openMosixWiki/index.php/OpenMosix2.6#Bug_Reporting 
>>
>> ) to solve it faster
>
> Doesn't seem to be random. I have a simple program that does  a long
> loop followed by an exit(). The loop gives me time to initiate
> migration. Once the loop completes on remote and does exit(), it hits
> a seg fault. I fugured the address of the segfault from the page fault
> handler in mm/fault.c, it seems to be coming from the C library pages
> that are copied.
>
> main()
> {
>    int a,b;
>
>    for(a=0;a<100000;a++)
>        for(b=0;b<100000;b++);
>
>    // compiler inserts exit() here.
> }
>
> The interesting thing is that this program does not segfault when
> compiled with '-static'. This fact confused me, since we are copying
> the process memory pages verbatim. Certain system calls always
> segfault, like exit(), nanosleep(), etc.
>
> My setup is 2 QEMUs running the Dec 22 release with TUN/TAP and
> etherbridge setup for netwoking between them. The QEMUs are running
> Debian Etch. Hope this is a good enough setup for debugging, or do I
> need 2 real machines?
>


Well, it sounds like a problem we had, what arch are you running ?

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