8.0RC2 amd64 - kernel panic running make buildworld

[Andriy Gapon]

on 13/11/2009 15:48 Kai Gallasch said the following:
> Am Fri, 13 Nov 2009 10:08:45 +0200
> schrieb Andriy Gapon <avg at icyb.net.ua>:
>> Kai,
>> I have a hunch, could you please try the following _sledgehammer_
>> patch (only kernel build/install is needed):
>> diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
>> index 44b71f3..a456609 100644
>> --- a/sys/amd64/amd64/pmap.c
>> +++ b/sys/amd64/amd64/pmap.c
>> @@ -2981,6 +2981,7 @@ setpte:
>>  	 * Map the superpage.
>>  	 */
>>  	pde_store(pde, PG_PS | newpde);
>> +	pmap_invalidate_all(pmap);
>>
>>  	pmap_pde_promotions++;
>>  	CTR2(KTR_PMAP, "pmap_promote_pde: success for va %#lx"
>>
>> This will slow down an act of promotion to a superpage, but should
>> not have any visible impact on overall performance.
> 
> Andriy,
> 
> I tried the patch with vm.pmap.pg_ps_enabled="1" , hw.mca.enabled="1"
> , rebuilt the kernel (although normally I never build kernels on Friday
> 13th :-) and ran buildworld -j8 for five times in a row. No sign of a
> machine check exception, no reboot.

I think that this is good news.
This is not a fix, but the fact that it helps should help us find a proper solution.

Thanks!
-- 
Andriy Gapon