About analyzing debug backtrace

Question

Currently I have a C++ program which crashed every now and then when running. I run it in Dr. Memory, but when it doesn't crash there is no obvious error reported, and when it does drmemory doesn't report anything at all (it just ends). So I debugged it with the shipped GDB in the corresponding MinGW package.

The program is compiled & linked with MinGW gcc 32bit (dwarf2 & sjlj produce similar results), under 64bit Windows 7. The GDB debugger caught a SIGSEGV that caused the program to crash. I made a complete backtrace, but I don't know how to analyze it, for I haven't done it before.

This is where the debugger stopped when the program crashed:

Thread 539 (Thread 5904.0x11b4):
#0  0x00000000 in ?? ()
No symbol table info available.
#1  0x00433f1b in pthread_create_wrapper ()
No symbol table info available.
#2  0x763d1287 in msvcrt!_itow_s () from C:\Windows\syswow64\msvcrt.dll
No symbol table info available.
#3  0x763d1328 in msvcrt!_endthreadex () from C:\Windows\syswow64\msvcrt.dll
No symbol table info available.
#4  0x74e5336a in KERNEL32!BaseThreadInitThunk () from C:\Windows\syswow64\kernel32.dll
No symbol table info available.
#5  0x77069f72 in ntdll!RtlInitializeExceptionChain () from C:\Windows\system32\ntdll.dll
No symbol table info available.
#6  0x77069f45 in ntdll!RtlInitializeExceptionChain () from C:\Windows\system32\ntdll.dll
No symbol table info available.
#7  0x00000000 in ?? ()
No symbol table info available.

I don't know if I should post other parts of the backtrace; it's very long, because the program is a multi-threaded Qt Gui program.

I guess the #0 00000000 in ?? () is where the program crashed, because in other threads there is always a new thread started after ... -> msvcrt!_endthreadex () -> msvcrt!_itow_s () -> pthread_create_wrapper ().

I've been debugging this for days...it's driving me up the wall. Any help will be greatly appreciated!!

P.S. Please let me know if I should post other parts of the backtrace too. I don't know whether the point GDB stopped is just the point problems popped in a multithreaded program.