Another reboot hang

[Svatopluk Kraus]

On Fri, Apr 29, 2016 at 8:52 PM, bob prohaska <fbsd at www.zefox.net> wrote:
> On Wed, Apr 27, 2016 at 05:15:49PM +0200, Svatopluk Kraus wrote:
>>
>> Those were general hints how to deal with such situation. In your
>> case, it looks more like an infinite waiting for something on another
>> thread not in your backtrace. So the all procs and locks dumps would
>> be unavoidable. And probably a backtrace of all threads too.
>>
>>
>
> So far the reboot hang hasn't repeated in half a dozen or so attempts.....
> not sure if that's good or bad.
>
> In the meantime the system ran stress2 (old version) for 12 hours 49 minutes,
> the previous record was around ten hours. Interestingly, the crash did _not_
> report "translation fault (L2)", but rather
> "panic: pmap_growkernel: no memory to grow kernel".


This panic is saying that there is no free page to alloc but the pmap
really needs it. I have no experience with such thing, but total
exhaustion of free page pool may happen probably. And when it happens
in some critical place, kernel has no possibility, but panic. BTW, it
would be nice to see output of 'show uma" and 'show malloc' from ddb.


>
> That's different, at least.
>
> Thanks for reading,
>
> bob prohaska
>