[mythtv-users] myth hangs + locks whole system [RAM OK]

[Ross Boylan]

On Thu, Aug 23, 2012 at 11:33 PM, Joseph Fry <joe at thefrys.com> wrote:

>
> On Thu, 2012-08-23 at 19:20 -0700, Ross Boylan wrote:
>> > At your implicit suggestion I'll try running memtest and see if it turns
>> > up anything.  The system is a few years old (5?).
>> >
>> memtest reported no errors after running for over 2 hours and 3 passes.
>> Ross
>>
>>
> Did you see if you were able to SSH into the system,
>
I attempted to ssh in, but did not get a connection until the system got
itself unstuck. (for both hangs).


> if mythweb was still responsive, etc.
>
I don't have mythweb.

>  In other words, is it possible that only the video or HID died, making
> the system appear frozen?
>
I don't think so, because ssh and other services were unresponsive too.
I'll describe the symptoms in more detail; perhaps you or someone else will
understand the role video might have played.

During the freeze there was a static image on the screen; the display of
the time never changed.  The mouse pointer was not visible and clicks and
typing appeared ineffective.  They were not totally lost, because I
attempted to switch to a non-graphical virtual terminal (ctl-F2) and when
the system came back it did switch to that terminal.  Also, the load for
the last 5 minutes showed as 60 (!).

>
> Reguardless, I am fairly certain, as are others in this thread (well the
> previous thread before you changed the subject), that your issue is not
> with Mythtv itself.  Perhaps you should try running it outside of the
> chroot and see if the problem persists?
>
I can't do that without upgrading the whole system.  When I do it will be
to the current stable release, squeeze, while the chroot is testing.  It
might be an experiment worth making.

I think for debugging I have to start with the apparent trigger, which is
myth.

The "no more queue slots" problem appears to have nothing to do with the
video, and is sort of a known bug: http://code.mythtv.org/trac/ticket/8698.
(or the even older 2496)  If I read that ticket right it is marked as fixed
in 0.24.  Unfortunately, I experienced it both in 0.24.2 and 0.25.2.  Would
it be useful to try to isolate the segment of the video that triggers the
problem?  Are there some tools I can use to extract chunks from my video?
I think I need a sample smaller than the whole recording for useful
debugging.

My original thought was that both of the original hangs I experienced had
the same root cause.  At least on the surface they differed (hang while
watching video; hang while transcoding).  It's also possible that during
the transcoding problem I also had a video problem.

>
> Good luck!
>
Thanks; I think I'll need it.

Swapping could well have a role, as Anthony pointed out.  The system can
crawl during heavy swapping, and given that the out of memory killer was
activated during one of the failures there must have been a lot of swapping
before that.  I'm not so sure that was the initial problem, however.  I did
not notice rising memory use before the failure.

Ross
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