Panic with latest pmap lock changes.

[Alan Cox]

On Sun, Jul 8, 2012 at 3:55 PM, Andreas Tobler <andreast-list at fgznet.ch>wrote:

> On 07.07.12 19:39, Alan Cox wrote:
>
>> On 07/07/2012 09:20, Justin Hibbits wrote:
>>
>>> Looks like I spoke too soon about the pmap lock changes working on my
>>> G4.  After about 24 hours of uptime, it panicked with the following:
>>>
>>> _rw_wlock_hard: recursing but non-recursive rw pmap pv global
>>> @ /home/chmeee/freebsd/src/sys/**powerpc/aim/mmu_oea.c:2301
>>>
>>> I think the attached patch should fix it (Untested, except for
>>> compiling).
>>>
>>>
>> Ugh.  Sorry.
>>
>> The attached patch eliminates the lock recursion.  While I was doing
>> that, I noticed that the pmap_ts_referenced() implementations on powerpc
>> have the wrong return type.  Oddly, the comments in mmu_if.h have the
>> return type correct, but the code two or three lines later has it wrong.
>>
>
> Fyi, I'm building world with the patch mentioned in this thread and the
> kernel updated to 238258. (G5-SMP 32-bit)
>
> So far it looks promising.
>
> Before 238258 I got reliable machine locks/freeze w/o any idea what was
> happening.
>
> If I reverted mmu_oea.c back to 238158, one before the commit from you
> Alan, I was able to get a successful full world/kernel build cycle.
> Yes, I confirmed that it booted, but I was not able to run a full
> world/kernel cycle since I lost my GEOM_APM config ;).
>
> Anyway, as said, it looks promising and it will take some hours to
> complete.
>
>
Should I commit the patch?

Alan