Login | Register For Free | Help
Search for: (Advanced)

Mailing List Archive: MythTV: Dev

another deadlock

 

 

MythTV dev RSS feed   Index | Next | Previous | View Threaded


mark at digivation

Nov 16, 2009, 2:16 AM

Post #1 of 4 (1504 views)
Permalink
another deadlock

Ive just seen this.

2009-11-16 20:00:29.883 Scheduler: Update next_record for 17202
2009-11-16 20:00:29.896 ERROR: Master backend tried to connect back to itself!

after which a restart watchdog kicked in.

2009-11-16 20:04:49.821 mythbackend version: [22823] www.mythtv.org

has the latest scheduler deadlock patch. no other evidence other than the log.

any suggestions where to look?
I did have idleTimeoutSecs at 0.
Are there any reasons not to set it to 30? only 1 master backend and no frontend activity at the time.

cheers
mark


Mark Spieth, PhD
Digivation Pty Ltd
9 Catalina Ave
ASHBURTON VIC 3147
Australia
Phone: +61 4 11 515 717 (0411515717)
Fax: +61 3 9885 5774


danielk at cuymedia

Nov 16, 2009, 5:32 AM

Post #2 of 4 (1402 views)
Permalink
Re: another deadlock [In reply to]

On Mon, 2009-11-16 at 21:16 +1100, Mark Spieth wrote:
> Ive just seen this.
>
> 2009-11-16 20:00:29.883 Scheduler: Update next_record for 17202
> 2009-11-16 20:00:29.896 ERROR: Master backend tried to connect back to
> itself!
>
> after which a restart watchdog kicked in.
>
> any suggestions where to look?

Add an assert(false); right after the "ERROR: .. " message so we
can locate and remove the offending code. :)

(Compile with debugging and either under gdb or with coredumps
enabled so that you can get a good backtrace.)

-- Daniel

_______________________________________________
mythtv-dev mailing list
mythtv-dev [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-dev


mark at digivation

Jan 25, 2010, 4:28 PM

Post #3 of 4 (961 views)
Permalink
Re: another deadlock [In reply to]

On 11/17/2009 12:32 AM, Daniel Kristjansson wrote:
> On Mon, 2009-11-16 at 21:16 +1100, Mark Spieth wrote:
>
>> Ive just seen this.
>>
>> 2009-11-16 20:00:29.883 Scheduler: Update next_record for 17202
>> 2009-11-16 20:00:29.896 ERROR: Master backend tried to connect back to
>> itself!
>>
>> after which a restart watchdog kicked in.
>>
>> any suggestions where to look?
>>
> Add an assert(false); right after the "ERROR: .. " message so we
> can locate and remove the offending code. :)
>
> (Compile with debugging and either under gdb or with coredumps
> enabled so that you can get a good backtrace.)
>
ok Ive finally got a useful backtrace. attached.
symptom is that the backend stops responding.

search for
"this=0xa7ba90|mtx = 0xa7bb5[89]"

4 threads want this lock. the one that has it is the TVRec::RunTV
TVRec::StartRecording thread which should be ok
Expirer thread
and HttpStatus request handling thread.

it appears as though the RunTV thread is wating for hwlock but cant get
it which means one of the other threads may be holding it.

I suspect DVBChannel hwlock should be inited as QMutex::Recursive
that should fix this.
will test but it doesn't happen often so feedback will take a while.

mark
Attachments: gcore.log.1264390476.gz (10.6 KB)


danielk at cuymedia

Jan 28, 2010, 8:30 PM

Post #4 of 4 (936 views)
Permalink
Re: another deadlock [In reply to]

On Tue, 2010-01-26 at 11:28 +1100, Mark Spieth wrote:
> ok Ive finally got a useful backtrace. attached.
> symptom is that the backend stops responding.

Can you open a ticket with this attached so it doesn't
get lost and also post the branch and revision (line
numbers aren't matching up for me).

-- Daniel

_______________________________________________
mythtv-dev mailing list
mythtv-dev [at] mythtv
http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-dev

MythTV dev RSS feed   Index | Next | Previous | View Threaded
 
 


Interested in having your list archived? Contact Gossamer Threads
 
  Web Applications & Managed Hosting Powered by Gossamer Threads Inc.