[mythtv] [BUG?] Threading / Sockets problem with master and slave backends

Malcolm Smith malc at porsche.demon.co.uk
Fri Sep 2 16:19:35 UTC 2005


Hi all,


Threading problems
 
I think there may be problems with Sockets or threads. (See attached bt).
 
I can reliably reproduce this problem.
 
Setup
Master Backend / Slave backend both in idle state. This only fails when 
a live slave backend in idle state is present
 
Method:
Open 2 browsers and request status simultaneously. The thread on the 
master backend handling status / web crashes, recording continues on 
both backend will remain in this state until killed. There is never any 
further response from the status port 6544/6543. (Sometimes it takes a 
few tries, so it's something to do with collision timing).
 
It can also be reproduced when requesting multiple activities via 
mythweb that take time to process (rescheds, status, deletes), but only 
ever when slave backend is present.
 
For background master has DVB, slave has DVB and PVR250 card. Master 
server also has mysql running on it.
Both backends are built from SVN from Weds 31 Aug, identical distributions.
 
back trace attached
 
Because of this the WAF is dropping, as she's impatient on the web.... 
help please.
 
 
Thread 12 (Thread 31009712 (LWP 4318)):
#0  0x001cf7a2 in _dl_sysinfo_int80 () from /lib/ld-linux.so.2
#1  0x02b9c7f6 in __nanosleep_nocancel () from /lib/tls/libc.so.6
#2  0x02bcad6a in usleep () from /lib/tls/libc.so.6
#3  0x007dbcaa in EITScanner::RunEventLoop (this=0x8109d90)
    at eitscanner.cpp:62
#4  0x007dbc6f in EITScanner::SpawnEventLoop (param=0x8109d90)
    at eitscanner.cpp:50
#5  0x0018e98c in start_thread () from /lib/tls/libpthread.so.0
#6  0x02bd17da in clone () from /lib/tls/libc.so.6
 
Thread 11 (Thread 129358768 (LWP 4439)):
#0  0x001cf7a2 in _dl_sysinfo_int80 () from /lib/ld-linux.so.2
#1  0x02b9c7f6 in __nanosleep_nocancel () from /lib/tls/libc.so.6
#2  0x02bcad6a in usleep () from /lib/tls/libc.so.6
#3  0x006c9364 in TVRec::RunTV (this=0x8101af0) at tv_rec.cpp:1612
#4  0x006c8dd9 in TVRec::EventThread (param=0x8101af0) at tv_rec.cpp:1534
#5  0x0018e98c in start_thread () from /lib/tls/libpthread.so.0
#6  0x02bd17da in clone () from /lib/tls/libc.so.6
 
Thread 10 (Thread 98745264 (LWP 4441)):
#0  0x001cf7a2 in _dl_sysinfo_int80 () from /lib/ld-linux.so.2
#1  0x00193eee in __lll_mutex_lock_wait () from /lib/tls/libpthread.so.0
#2  0x00190df4 in _L_mutex_lock_29 () from /lib/tls/libpthread.so.0
#3  0xf6e00010 in ?? ()
#4  0xf6f48cf8 in ?? ()
#5  0x070d5214 in ?? () from /usr/lib/qt-3.3/lib/libqt-mt.so.3
#6  0x00a76ee0 in ?? ()
#7  0x080ef278 in ?? ()
#8  0x05e2b5f8 in ?? ()
#9  0x06f972f0 in QRecursiveMutexPrivate::lock ()
   from /usr/lib/qt-3.3/lib/libqt-mt.so.3 Previous frame identical to 
this frame (corrupt stack?)
 
 



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