8.0RC2 amd64 - kernel panic running make buildworld
Attilio Rao
attilio at freebsd.org
Tue Nov 17 14:30:35 UTC 2009
2009/11/17 Andriy Gapon <avg at icyb.net.ua>:
> on 14/11/2009 11:36 Andriy Gapon said the following:
>> on 14/11/2009 03:21 Kai Gallasch said the following:
>>> Hi. The patch did help for surviving a makeworld.
>>>
>>> But now I have another machine check exception with this server. It
>>> happened with your patch active, and vm.pmap.pg_ps_enabled="1". I
>>> copied data from a remote server by NFS mount to the instable server.
>>> Destination was a local ZFS filesystem.
>>>
>>> ----------------
>>>
>>> sonnenkraft:~ # MCA: CPU 7 UNCOR PCC OVER DTLB L1 error
>>> MCA: Address 0xff800d860000
>>
>> It's interesting because the same happened to me too, only in my case it was
>> zpool scrub that triggered it.
>> I will try to look into this further.
>>
>
> Kai,
>
> the latest patch in the works, it's against a clean tree:
>
> diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
> index 44b71f3..ff35eb9 100644
> --- a/sys/amd64/amd64/pmap.c
> +++ b/sys/amd64/amd64/pmap.c
> @@ -2365,6 +2365,9 @@ pmap_demote_pde
> * the read above and the store below.
> */
> pde_store(pde, newpde);
> + pmap_invalidate_page(pmap, va);
> + clflush((vm_offset_t)vtopde(va));
> + mfence();
>
> /*
> * Invalidate a stale recursive mapping of the page table page.
> @@ -2981,6 +2984,11 @@ setpte:
> * Map the superpage.
> */
> pde_store(pde, PG_PS | newpde);
> + pmap_invalidate_range(pmap, va & ~PDRMASK, (va & ~PDRMASK) + NBPDR);
> + clflush((vm_offset_t)vtopde(va));
> + mfence();
> + if (va >= VM_MAXUSER_ADDRESS)
> + pmap_invalidate_page(pmap, (vm_offset_t)vtopte(va));
>
> pmap_pde_promotions++;
> CTR2(KTR_PMAP, "pmap_promote_pde: success for va %#lx"
>
I think you should use mb() rather than mfence().
Thanks,
Attilio
--
Peace can only be achieved by understanding - A. Einstein
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