stopping amd causes a freeze

[Ronald Klop]

On Mon, 22 Jul 2013 14:19:44 +0200, Dominic Fandrey <kamikaze at bsdforen.de>  
wrote:

> On 22/07/2013 12:07, Konstantin Belousov wrote:
>> On Mon, Jul 22, 2013 at 11:50:24AM +0200, Dominic Fandrey wrote:
>>> Occasionally stopping amd freezes my system. It's a rare occurrence,
>>> and I haven't found a reliable way to reproduce it.
>>>
>>> It's also a real freeze, so there's no way to get into the debugger
>>> or grab a core dump. I only can perform the 4 seconds hard shutdown to
>>> revive the system.
>>>
>>> I run amd through sysutils/automounter, which is a scripting solution
>>> that generates an amd.map file based on encountered devices and devd
>>> events. The SIGHUP it sends to amd to tell it the map file was updated
>>> does not cause problems, only a SIGKILL may cause the freeze.
>>>
>>> Nothing was mounted (by amd) during the last freeze.
>>>
>>> I don't see any angle to tackle this, but I'm throwing it out here
>>> any way, in the hopes that someone actually has an idea how to approach
>>> the issue.
>>
>> Are you sure that the machine did not paniced ?  Do you have serial  
>> console ?
>
> No, I don't have one. All that I can tell is that everything freezes
> (i.e. Xorg screen and mouse). ACPI events like shutdown don't cause a
> reaction. And the system doesn't respond to ICMP queries.
>
>> The amd(8) locks itself into memory, most likely due to the fear of
>> deadlock. There are some known issues with user wirings in stable/9.
>> If the problem you see is indeed due to wiring, you might try to apply
>> r253187-r253191.
>
> From head? That may be worth a try. It would be better for testing if I
> managed to reproduce the problem reliably, before I test patches.
>
> I see it's scheduled for MFC, soon.
>

Did you try a run with the INVARIANTS, etc. options in the kernel? That  
enables more sanity checking for locks which is too slow for production.

Ronald.