Fwd: gdb on Cygwin cannot give correct call stacks for segment faults

[Eli Zaretskii]

> Date: Mon, 28 Oct 2013 12:00:17 +0800
> From: Pan ruochen <panruochen@gmail.com>
> 
> Program received signal SIGSEGV, Segmentation fault.
> 0x61138b61 in _fwrite_r () from /usr/bin/cygwin1.dll
> (gdb) backtrace
> #0  0x61138b61 in _fwrite_r () from /usr/bin/cygwin1.dll
> #1  0x76bd1194 in WaitForSingleObjectEx ()
>    from /cygdrive/c/windows/syswow64/kernel32.dll
> #2  0x76bd1148 in WaitForSingleObject ()
>    from /cygdrive/c/windows/syswow64/kernel32.dll
> #3  0x610dd558 in sig_send(_pinfo*, siginfo_t&, _cygtls*) ()
>    from /usr/bin/cygwin1.dll
> #4  0x610303b4 in exception::handle(_EXCEPTION_RECORD*,
> _exception_list*, _CONTEXT*, void*) () from /usr/bin/cygwin1.dll
> #5  0x77a5b499 in ntdll!LdrRemoveLoadAsDataTable ()
>    from /cygdrive/c/windows/system32/ntdll.dll
> #6  0x0028a6ac in ?? ()
> #7  0x77a5b46b in ntdll!LdrRemoveLoadAsDataTable ()
>    from /cygdrive/c/windows/system32/ntdll.dll
> #8  0x0028a6ac in ?? ()
> #9  0x77a10133 in ntdll!KiUserExceptionDispatcher ()
>    from /cygdrive/c/windows/system32/ntdll.dll
> #10 0x0028a6ac in ?? ()
> #11 0x61138c75 in fwrite () from /usr/bin/cygwin1.dll
> #12 0x610d75e5 in _sigfe () from /usr/bin/cygwin1.dll
> #13 0x0000000d in ?? ()
> #14 0x00000000 in ?? ()
> 
> does not give any useful clues where the segment faults arise.
> So what is wrong?

My crystal ball says you are looking at the wrong thread.  Try "thread
apply all backtrace".