Re: FreeBSD 8.0-BETA2/amd64 crashes on SMP under load

From: Marcel Moolenaar <xcllnt_at_mac.com>
Date: Fri, 31 Jul 2009 11:01:49 -0700
On Jul 31, 2009, at 10:25 AM, John Baldwin wrote:
>> In other words: kgdb was designed to hide FreeBSD specifics from the
>> core GDB
>> code, because core GDB doesn't know how to deal with all FreeBSD
>> details.
>> Revision 178670 created a stronger dependency on core GDB and as such
>> broke
>> architectures that core GDB doesn't support for FreeBSD.
>
> So gdb doesn't work for core dumps on regular processes under ia64?

It does, but kernel core files aren't matched, because the OSABI
is standalone. Also, GDB doesn't have libkvm support for ia64,
which is probably what makes it work on i386/amd64.

>  Still,
> kgdb doesn't actually use the regular core target at all, it uses  
> its own
> target that uses libkvm to service the actual memory I/O that  
> normally goes
> to the core target.

That's maybe the problom: is the kgdb target used at all?
If it were, then why did ia64 break?

Maybe we have a simple resolution problem where GDB just
happens to pick the wrong core_stratum target on ia64...

I haven't had the time for root cause hunting, so from here
on things should be taken with plenty of salt. I can check
PowerPC for example...

>  The previous code was very hacky and didn't allow you
> to use the 'file' and 'core' commands as a result.

Actually it was by design.

-- 
Marcel Moolenaar
xcllnt_at_mac.com
Received on Fri Jul 31 2009 - 16:02:04 UTC

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