[mythtv-commits] Ticket #4820: Segfault in scheduler thread

[MythTV]

#4820: Segfault in scheduler thread
------------------------------------------------+---------------------------
 Reporter:  Mike Rice <mikerice1969 at gmail.com>  |        Owner:  ijr    
     Type:  defect                              |       Status:  new    
 Priority:  minor                               |    Milestone:  unknown
Component:  mythtv                              |      Version:  head   
 Severity:  medium                              |   Resolution:         
  Mlocked:  0                                   |  
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Comment(by tim at electronghost.co.uk):

 Replying to [ticket:4820 Mike Rice <mikerice1969 at gmail.com>]:
 > Running SVN trunk 16313.  May just be memory corruption but hopefully
 someone can see something wrong from the trace.  The full stack trace is
 attached.
 >

 I'm seeing an abort from glibc when channel hopping in LiveTV. It looks to
 me like a memory corruption somewhere. I added

 if (me->Message().left(6) == "SIGNAL") {
     QString crashme=me->ExtraDataList().join(" ");
 }

 at the top of the various checks in MainServer::customEvent() in
 mythbackend/mainserver.cpp and this line triggers the crash according to
 kdbg and the resulting coredump. The QStringList is complete gibberish at
 this point.

 However, I also added comparable QString crashme=slist.join(" ")
 statements into the 3 places where the SIGNAL message is generated and
 none of them fired, which suggests to me that something is scribbling on
 memory somewhere else.

 valgrind is hard to use in this case but it does have several complaints
 I'm investigating. I may be able to do some more poking this evening. It
 looks like the backend is often calling RemoteFile::openSocket() while
 RemoteFile::path is either NULL or undefined.

 I'm running with separate back and front ends, both on x86_64, and have
 gone down to -O0 in the compile flags to make debugging easier/possible
 :-)

-- 
Ticket URL: <http://svn.mythtv.org/trac/ticket/4820#comment:2>
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