mythtv-core.25: mythbackend crashes when accessed by UPNP clients

[james.george@…]

I'm seeing repeatable crashes in the mythbackend when accessing it via UPNP clients (e.g. 8Player) or TORC (all iOS apps running on iPad).

The mythbackend log shows no activity prior to crash, however, I'll attach one. Crash log from mythbackend is attached with an excerpt below:

Thread 21 Crashed:
0   libunwind.dylib                     0x00007fff971afe9c libunwind::CompactUnwinder_x86_64<libunwind::LocalAddressSpace>::stepWithCompactEncodingFrameless(unsigned int, unsigned long long, libunwind::LocalAddressSpace&, libunwind::Registers_x86_64&, bool) + 548
1   libunwind.dylib                     0x00007fff971ad5c0 libunwind::CompactUnwinder_x86_64<libunwind::LocalAddressSpace>::stepWithCompactEncoding(unsigned int, unsigned long long, libunwind::LocalAddressSpace&, libunwind::Registers_x86_64&) + 86
2   libunwind.dylib                     0x00007fff971ad50e libunwind::UnwindCursor<libunwind::LocalAddressSpace, libunwind::Registers_x86_64>::step() + 58
3   libunwind.dylib                     0x00007fff971acbd7 _Unwind_RaiseException + 83
4   libc++abi.dylib                     0x00007fff92c59baa __cxa_rethrow + 72
5   libmythupnp-0.25.0.dylib            0x00000001060a2a08 MethodInfo::Invoke(Service*, QMap<QString, QString> const&) + 2056
6   libmythupnp-0.25.0.dylib            0x00000001060a486f ServiceHost::ProcessRequest(HTTPRequest*) + 3823
7   libmythupnp-0.25.0.dylib            0x0000000106063fc2 HttpServer::DelegateRequest(HTTPRequest*) + 226
8   libmythupnp-0.25.0.dylib            0x0000000106064572 HttpWorker::run() + 770
9   libmythbase-0.25.0.dylib            0x000000010615a0e4 MPoolThread::run() + 388
10  libQtCore.4.dylib                   0x00000001084071af QThreadPrivate::start(void*) + 373
11  libsystem_c.dylib                   0x00007fff9a4f2782 _pthread_start + 327
12  libsystem_c.dylib                   0x00007fff9a4df1c1 thread_start + 13

Please let me know if you need any further information.

[ctreleaven (Craig Treleaven)]

Thanks for the report

I hadn't tested UPNP yet. My Sony TV pauses for a long time trying to access the mythbackend and then complains that it can't find any content. The backend doesn't crash, though.

Just to be sure, your UPNP clients can access myth under Linux, right?

Please provide some more detailed logs. Stop the backend and then edit /opt/local/Library/LaunchDaemons/org.mythtv.mythbackend.plist as follows:

• Save a copy of the original plist.
• Change:

          <string>info</string>
  

  To:

          <string>debug</string>
  

• Add:

          <string>--verbose</string>
          <string>none,upnp</string>
  

Then start the backend again and try to access it with a UPNP device. Hopefully, we'll get more detailed logs

Change the plist back after the test and restart the backend so it doesn't flood your system with logs.

[ryandesign (Ryan Carsten Schmidt)]

James, remember to put the port name into the Port and Summary fields.

Craig, remember to use WikiFormatting when writing in Trac, and preview before submitting to ensure it looks the way you want.

[james.george@…]

Replying to ctreleaven@…:

Thanks for the report

I hadn't tested UPNP yet. My Sony TV pauses for a long time trying to access the mythbackend and then complains that it can't find any content. The backend doesn't crash, though.

Just to be sure, your UPNP clients can access myth under Linux, right?

Please provide some more detailed logs. Stop the backend and then edit /opt/local/Library/LaunchDaemons/org.mythtv.mythbackend.plist as follows:

• Save a copy of the original plist.
• Change:

          <string>info</string>
  

  To:

          <string>debug</string>
  

• Add:

          <string>--verbose</string>
          <string>none,upnp</string>
  

Then start the backend again and try to access it with a UPNP device. Hopefully, we'll get more detailed logs

Change the plist back after the test and restart the backend so it doesn't flood your system with logs.

Yes, the UPNP clients are fine accessing a Linux-based mythbackend. Most of the UPNP clients can browse the share, but accessing for the most part either does not return video, or crashes the backend. In a few cases, I have had video start to playback, but usually after a backend crash.

I will attach the log file with elevated logging. I couldn't see anything useful in the log though... any other logging thoughts?

[james.george@…]

Mythbackend log [--loglevel debug --verbose none,upnp]

[james.george@…]

Ok, I've just done some further testing and I've uncovered two things.

Firstly, I should be wearing the dunce hat, UPNP clients do not make the back end crash. The failures with the UPNP clients was due to the migration of my mythbackend from Mythbuntu to OS X macports - the hostname in the RECORDED table was incorrect - this caused issues with MythWeb (which I've got working BTW!) thumbnail generation. Once fixed, not only was MythWeb happier, but the issues with the UPNP clients went away too.

Secondly, I definitely am seeing repeatable crashes with the mythbackend, but it is with Torc, which is not using UPNP, but rather the web service interface (i.e. check out notes on ​http://fecitfacta.com/blog1/torc/ and ​http://server:6544). Accessing these via macports mythbackend seems to work fine, but starting Torc, or making Torc refresh, crashes the backend. Torc still works with the backend once it restarts, but I don't see thumbnails etc.

The original premise for this ticket (UPNP crashes) isn't valid, so whether you would prefer to close this ticket and open another one specifically for Torc/Webservices, I'll leave up to you.

Cheers!

[ctreleaven (Craig Treleaven)]

Thanks for your testing work and reporting back.

I haven't looked at Torc at all. I've played briefly with HTTP Live Stream to iOS devices with good results (even an orginal iPad and iPhone 3GS). I can't supply much support for Torc. Perhaps you could raise it with the developer.

Could you please contact me off the bug tracker regarding mythweb?