[mythtv] DVB Segfault - With bad streams

Steve Davies steve at one47.co.uk
Mon Nov 10 17:26:06 EST 2003


Hi,

This is a "fun" one, probably the longest gdb backtrace I have ever seen!

I have 2 aerials, and one of them is not too hot on the reception of the lower 
frequencies. This causes problems with about 5 of my DVB-T channels, on one 
mux. If I try to receive one of these channels, as you would expect, I will 
get LOTS of the following:

2003-11-10 20:08:03 DVB#0 WARNING - Transport Stream Continuity Error.
2003-11-10 20:08:03 DVB#0 WARNING - Transport Stream Continuity Error.
2003-11-10 20:08:03 DVB#0 WARNING - Transport Stream Continuity Error.
2003-11-10 20:08:03 DVB#0 WARNING - Transport Stream Continuity Error.
2003-11-10 20:08:03 DVB#0 WARNING - Transport Stream Continuity Error.
2003-11-10 20:08:03 DVB#0 WARNING - Transport Stream Continuity Error.

Unfortunately, after a few seconds, I then get a mythbackend segfault. I have 
snipped around 32,000 lines from the start of the backtrace output, as they 
are all identical. Does this look like stack corruption? I have no idea why 
XineramaQueryScreens would be called at this time!

      |--Yes, this is the correct number!
vvvvvv
#16312 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16313 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16314 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16315 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16316 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16317 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16318 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16319 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16320 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16321 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16322 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
---Type <return> to continue, or q <return> to quit---
#16323 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16324 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16325 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16326 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16327 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16328 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16329 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16330 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16331 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16332 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16333 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
---Type <return> to continue, or q <return> to quit---
#16334 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16335 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16336 0x0830e38f in XineramaQueryScreens ()
No symbol table info available.
#16337 0x0830ec70 in XineramaQueryScreens ()
No symbol table info available.
#16338 0x080f2842 in QMapNode<int, QString>::~QMapNode() ()
No symbol table info available.
#16339 0x080cf6ea in std::iterator<std::random_access_iterator_tag, QString, 
int, QString*, QString&>::iterator() ()
No symbol table info available.
#16340 0x40a35e31 in pthread_start_thread () from /lib/libpthread.so.0
No symbol table info available.

#16341 0x40a35eaf in pthread_start_thread_event () from /lib/libpthread.so.0
No symbol table info available.

#16342 0x40c3a30a in clone () from /lib/libc.so.6
No symbol table info available.

Thread 14 (Thread 196621 (LWP 31057)):
#0  0x40c0aac6 in nanosleep () from /lib/libc.so.6

---Type <return> to continue, or q <return> to quit---
No symbol table info available.

Thread 13 (Thread 180236 (LWP 31051)):
#0  0x40a3c426 in nanosleep () from /lib/libpthread.so.0

No symbol table info available.

Thread 12 (Thread 163851 (LWP 31050)):
#0  0x40a385d4 in __pthread_sigsuspend () from /lib/libpthread.so.0
No symbol table info available.

#1  0x40a38398 in __pthread_wait_for_restart_signal ()
    from /lib/libpthread.so.0
No symbol table info available.
#2  0x00000020 in ?? ()
No symbol table info available.
#3  0xbe5ff958 in ?? ()
No symbol table info available.
#4  0xb0000000 in ?? ()
No symbol table info available.


Thread 11 (Thread 147466 (LWP 31049)):
#0  0x40a385d4 in __pthread_sigsuspend () from /lib/libpthread.so.0
No symbol table info available.

---Type <return> to continue, or q <return> to quit---
#1  0x40a38398 in __pthread_wait_for_restart_signal ()
    from /lib/libpthread.so.0
No symbol table info available.
#2  0x00000020 in ?? ()
No symbol table info available.
#3  0xbe7ff958 in ?? ()
No symbol table info available.
#4  0xb0000000 in ?? ()
No symbol table info available.

Thread 10 (Thread 131081 (LWP 31048)):

#0  0x40a385d4 in __pthread_sigsuspend () from /lib/libpthread.so.0
No symbol table info available.
#1  0x40a38398 in __pthread_wait_for_restart_signal ()
    from /lib/libpthread.so.0
No symbol table info available.

#2  0x00000020 in ?? ()
No symbol table info available.
#3  0xbe9ff958 in ?? ()
No symbol table info available.
#4  0xb0000000 in ?? ()
No symbol table info available.
---Type <return> to continue, or q <return> to quit---

Thread 9 (Thread 114696 (LWP 31047)):
#0  0x40a385d4 in __pthread_sigsuspend () from /lib/libpthread.so.0
No symbol table info available.

#1  0x40a38398 in __pthread_wait_for_restart_signal ()
    from /lib/libpthread.so.0
No symbol table info available.
#2  0x00000020 in ?? ()
No symbol table info available.
#3  0xbebff958 in ?? ()
No symbol table info available.


Thread 8 (Thread 98311 (LWP 31046)):
#0  0x40c0aac6 in nanosleep () from /lib/libc.so.6
No symbol table info available.

Thread 7 (Thread 81926 (LWP 31045)):

#0  0x40c0aac6 in nanosleep () from /lib/libc.so.6
No symbol table info available.

Thread 6 (Thread 65541 (LWP 31044)):

#0  0x40c0aac6 in nanosleep () from /lib/libc.so.6
---Type <return> to continue, or q <return> to quit---
No symbol table info available.

Thread 5 (Thread 49156 (LWP 31043)):

#0  0x40c0aac6 in nanosleep () from /lib/libc.so.6
No symbol table info available.

Thread 4 (Thread 32771 (LWP 31041)):
#0  0x40c0aac6 in nanosleep () from /lib/libc.so.6
No symbol table info available.


Thread 3 (Thread 16386 (LWP 31040)):
#0  0x40c0aac6 in nanosleep () from /lib/libc.so.6
No symbol table info available.

Thread 2 (Thread 32769 (LWP 31039)):
#0  0x40c3161a in poll () from /lib/libc.so.6
No symbol table info available.
#1  0x40a35b30 in __pthread_manager () from /lib/libpthread.so.0
No symbol table info available.
#2  0x40a35d37 in __pthread_manager_event () from /lib/libpthread.so.0
No symbol table info available.
#3  0x40c3a30a in clone () from /lib/libc.so.6
---Type <return> to continue, or q <return> to quit---
No symbol table info available.

Thread 1 (Thread 16384 (LWP 31029)):
#0  0x40c33aa1 in select () from /lib/libc.so.6
No symbol table info available.
#1  0x4094d024 in ?? () from /usr/lib/libqt-mt.so.3
No symbol table info available.
#0  0x0830dd71 in XineramaQueryScreens ()
(gdb)


This might be partly due to bad parameters in one of my table columns - I have 
just fixed my "fec" and "lp_code_rate" parameters based on a post by Matt 
Jarvis. OTOH I believe I did also manage to cause it on what I believe is a 
well configured channel.

Kind regards,
Steve

-- 
Steve Davies                   steve at one47.co.uk

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