[mythtv] [mythtv-commits] Ticket #6725: segmentation fault in mythbackend

Simon Kenyon simon at koala.ie
Thu Jul 16 13:23:25 UTC 2009


Nick Morrott wrote:
> On 16/07/2009, Simon Kenyon <simon at koala.ie> wrote:
>   
>> MythTV wrote:
>>
>>     
>>> #6725: segmentation fault in mythbackend
>>>
>>>       
>> -------------------------------------------+--------------------------------
>>     
>>>  Reporter:  Simon Kenyon <simon at koala.ie>  |        Owner:  danielk
>>>       
>>    Type:  defect                         |       Status:  infoneeded_new
>>     
>>>  Priority:  minor                          |    Milestone:  unknown
>>>       
>> Component:  MythTV - DVB/ATSC              |      Version:  head
>> Severity:  medium                         |   Resolution:
>> Mlocked:  0                              |
>> -------------------------------------------+--------------------------------
>>     
>>> Changes (by stuarta):
>>>
>>>  * status:  new => infoneeded_new
>>>
>>>
>>>
>>>
>>>       
>>  what more information do you need?
>>  i'm a little confused
>>  not sure if you need additional information from me
>>
>>  the backend has a PVR-350 connected to a STB using RGB
>>  it has two DVB-S cards, a Nexus-S and and a budget 1500
>>  it is hard to tell remotely, but i think i am using the 1500
>>  i only have one DVB card configured in at the moment
>>     
>
> Your second log contains:
>
> 2009-07-14 09:40:03.310 MythSocket(909c40:36): readStringList: Error, timeout.
> 2009-07-14 09:40:03.314 Slave backend: newyork no longer connected
> 2009-07-14 09:40:03.315 PlaybackSock::SendReceiveStringList(): No response.
> 2009-07-14 09:40:03.315 Reschedule requested for id 0.
> 2009-07-14 09:40:03.315 PlaybackSock, Error: IsBusy:
> QUERY_REMOTEENCODER 61 gave us no response.
>
> Do you mean to have a slave backend on the network? If you do, is it cardless?
>   
i do have a slave backend
it has one DVB-S and one dual DVB-T card
> Echoing Mike Dean's frequent suggestion, I would do a "Delete all
> capture cards" and then just configure the card you are using for
> testing. Your log indicated you are using the DVB-S card that uses the
> "ST STV0299 DVB-S" frontend (DVB adapter 1).
>   
but as you know yourself, deleting all capture cards and adding them 
again is a bit drastic
this is a production system - i'm not using it for "testing" - i'm using 
it for "watching" :-)
> I've not had any mythbackend stability issues on trunk @ 20830. The
> channel scanner is borken, but once up and running the backend seems
> fairly stable (IME).
>   
ok. that is good to know
> The other thing I noticed looking through your second log is that your
> backend is trying to tune to serviceid 1111 on the 11344000H mux:
>
> 2009-07-14 09:35:17.270 DVBChan(46:/dev/dvb/adapter1/frontend0):
> Opening DVB channel
> 2009-07-14 09:35:17.270 DVBChan(46:/dev/dvb/adapter1/frontend0):
> SetChannelByString(1111):
> 2009-07-14 09:35:17.279 DVBChan(46:/dev/dvb/adapter1/frontend0):
> 11344500 qpsk a auto auto a a auto a h
> 2009-07-14 09:35:17.280 DVBChan(46:/dev/dvb/adapter1/frontend0): Old
> Params: 11623080 qpsk a auto auto a a auto a h
> 			DVBChan(46:/dev/dvb/adapter1/frontend0): New Params: 11344500 qpsk
> a auto auto a a auto a h
> 2009-07-14 09:35:17.280 DVBChan(46:/dev/dvb/adapter1/frontend0):
> Tune(): Tuning to 1594500kHz
> 2009-07-14 09:35:17.281 dvbchannel.cpp:wait_for_backend: Status:
> 2009-07-14 09:35:17.281 DVBChan(46:/dev/dvb/adapter1/frontend0):
> Tune(): Frequency tuning successful.
> 2009-07-14 09:35:17.282 DVBChan(46:/dev/dvb/adapter1/frontend0):
> SetChannelByString(1111): Tuned to frequency.
> 2009-07-14 09:35:17.282 TVRec(46): Starting Signal Monitor
> 2009-07-14 09:35:17.283 TVRec(46): SetupSignalMonitor(1, 0)
> 2009-07-14 09:35:17.283 DVBChan(46:/dev/dvb/adapter1/frontend0):
> Opening DVB channel
> 2009-07-14 09:35:17.284 DVBSM(/dev/dvb/adapter1/frontend0): Can
> measure Signal Strength
> 2009-07-14 09:35:17.285 DVBSM(/dev/dvb/adapter1/frontend0): Can measure S/N
> 2009-07-14 09:35:17.286 DVBSM(/dev/dvb/adapter1/frontend0): Can
> measure Bit Error Rate
> 2009-07-14 09:35:17.286 DVBSM(/dev/dvb/adapter1/frontend0), Warning:
> Can not count Uncorrected Blocks
> 			eno: Function not implemented (38)
> 2009-07-14 09:35:17.287 SM(/dev/dvb/adapter1/frontend0)::RemoveFlags:
> Seen() Match() Wait(UB,)
> 2009-07-14 09:35:17.287 DVBSM(/dev/dvb/adapter1/frontend0):
> DVBSignalMonitor::ctor initial flags Seen() Match() Wait(Sig,SNR,BER,)
> 2009-07-14 09:35:17.590 TVRec(46): Signal monitor successfully created
> 2009-07-14 09:35:17.590 TVRec(46): Setting up table monitoring.
> 2009-07-14 09:35:17.593 Using profile 'Live TV' to record
> 2009-07-14 09:35:17.593 TVRec(46): DVB service_id 1111 on net_id 2 tsid 2313
> 2009-07-14 09:35:17.594
> DTVSM(/dev/dvb/adapter1/frontend0)::SetDVBService(transport_id: 2313,
> network_id: 2, service_id: 1111):
>
>
> No such serviceid exists on that mux - so I'm not sure if the backend
> is getting stuck somewhere, or if it gracefully recovers and segfaults
> somewhere else later independent of this. You might try creating a new
> temporary video source and then import a current channels.conf created
> by dvbscan (or equivalent on Gentoo) so that your channels are all
> good.
>
> Cheers,
> Nick
>
>   
it seems that if you get the channel list out of sync with what is being 
broadcast, then the backend becomes unstable
as you know yourself, the channels that are broadcast on Astra 28.2E 
change on an almost daily basis

anyway. i will do as you say
pity. i had more or less got my channel list sorted out

--
simon


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