[mythtv-users] Help with backtrace - Does this look right?

A McDermott list at mcdermotts.ca
Wed May 2 14:19:58 UTC 2012


I am trying to capture a backtrace of a segfault within libQtcore.so.4
on my backend.  For example:

May  1 13:59:54 pvr kernel: [173048.994311] mythbackend[13043]:
segfault at 48 ip 00007f1e0d4d8cbd sp 00007f1dfdbc4cd0 error 4 in
libQtCore.so.4.7.4[7f1e0d359000+292000]

When logs rotated today, gdb caught the HUP and printed a backtrace -
which I understand.  What I am curious about is the number of "No
Symbol table info available" entries in the backtrace entries - see
"Thread #3" below.  Some threads do have symbols available (looks like
from within myth itself not the libraries - see "thread #1" below)

My question is does this look correct?  When gdb finally captures the
actual segfault, will this be sufficient information for the ticket?
Or, do I need to do something else to get symbols for the various
libraries?

Thread 3 (Thread 0x7fffdffff700 (LWP 1817)):
#0  0x00007ffff5fff3cb in pthread_cond_timedwait@@GLIBC_2.3.2 () from
/lib/x86_64-linux-gnu/libpthread.so.0
No symbol table info available.
#1  0x00007ffff429111e in QWaitCondition::wait(QMutex*, unsigned long)
() from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
No symbol table info available.
#2  0x00007ffff6d76797 in LoggerThread::run (this=0x7f1690) at logging.cpp:826
        item = 0x7fffe035aab0
        qLock = {val = 140737337401209}
#3  0x00007ffff4290d05 in ?? () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
No symbol table info available.
#4  0x00007ffff5ffaefc in start_thread () from
/lib/x86_64-linux-gnu/libpthread.so.0
No symbol table info available.
#5  0x00007ffff37ac59d in clone () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#6  0x0000000000000000 in ?? ()
No symbol table info available.

Thread 1 (Thread 0x7ffff7fc67a0 (LWP 1813)):
#0  0x00007ffff37a0473 in poll () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#1  0x00007fffeef25f68 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#2  0x00007fffeef26429 in g_main_context_iteration () from
/lib/x86_64-linux-gnu/libglib-2.0.so.0
No symbol table info available.
#3  0x00007ffff43a2ed6 in
QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>)
() from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
No symbol table info available.
#4  0x00007ffff4376cf2 in
QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) ()
from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
No symbol table info available.
#5  0x00007ffff4376ef7 in
QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from
/usr/lib/x86_64-linux-gnu/libQtCore.so.4
No symbol table info available.
#6  0x00007ffff437b789 in QCoreApplication::exec() () from
/usr/lib/x86_64-linux-gnu/libQtCore.so.4
No symbol table info available.
#7  0x000000000050525d in run_backend (cmdline=<optimized out>) at
main_helpers.cpp:654
        ismaster = true
        __FUNCTION__ = "run_backend"
        fatal_error = false
        sysEventHandler = 0x85a6c0
        runsched = <optimized out>
        httpStatus = 0x8c25a0
        pHS = 0x89d4f0
        port = 6543
        sched = 0x80aa60
        exitCode = <optimized out>
#8  0x0000000000423023 in main (argc=6, argv=<optimized out>) at main.cpp:127
        a = <incomplete type>
        retval = <optimized out>
        mask = {static null = {<No data fields>}, static shared_null =
{ref = {_q_value = 17533}, alloc = 0, size = 0, data = 0x7ffff46aaefa,
clean = 0, simpletext = 0, righttoleft = 0, asciiCache = 0, capacity =
0, reserved = 0, array = {0}}, static shared_empty = {ref = {_q_value
= 3224}, alloc = 0, size = 0, data = 0x7ffff46aaeda, clean = 0,
simpletext = 0, righttoleft = 0, asciiCache = 0, capacity = 0,
reserved = 0, array = {0}}, d = 0x7e7b60, static codecForCStrings =
0x0}
        __FUNCTION__ = "main"
        cmdline = {<MythCommandLineParser> =
{_vptr.MythCommandLineParser = 0x7a3e30, m_appname = {static null =
{<No data fields>}, static shared_null = {ref = {_q_value = 17533},
alloc = 0, size = 0, data = 0x7ffff46aaefa, clean = 0, simpletext = 0,
righttoleft = 0, asciiCache = 0, capacity = 0, reserved = 0, array =
{0}}, static shared_empty = {ref = {_q_value = 3224}, alloc = 0, size
= 0, data = 0x7ffff46aaeda, clean = 0, simpletext = 0, righttoleft =
0, asciiCache = 0, capacity = 0, reserved = 0, array = {0}}, d =
0x7d4bf0, static codecForCStrings = 0x0}, m_optionedArgs = {{d =
0x7d5620, e = 0x7d5620}}, m_namedArgs = {{d = 0x7d54f0, e =
0x7d54f0}}, m_passthroughActive = false, m_overridesImported = true,
m_verbose = false}, <No data fields>}
        daemonize = <optimized out>


More information about the mythtv-users mailing list