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Date: Wed, 20 Sep 2006 10:48:36 -0400
From: Christopher Faylor <cgf-no-personal-reply-please AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: gdb attach to process to produce stacktrace
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On Wed, Sep 20, 2006 at 07:06:45AM -0700, Hans Horn wrote:
>for quite some time I was trying to figure out (e.g. 
>http://thread.gmane.org/gmane.os.cygwin/58420/focus=58420) how to attach gdb 
>to a process in order to produce a useful stacktrace.
>
>All attempts however produced something useless like the following:
>
>[Switching to thread 1096.0x7f4]
>* 4 thread 1096.0x7f4  0x7c901231 in ntdll!DbgUiConnectToDbg () from 
>/cygdrive/c/WINDOWS/system32/ntdll.dll
>  3 thread 1096.0xce0  0x7c90eb94 in ntdll!LdrAccessResource () from 
>/cygdrive/c/WINDOWS/system32/ntdll.dll
>  2 thread 1096.0x8ec  0x7c90eb94 in ntdll!LdrAccessResource () from 
>/cygdrive/c/WINDOWS/system32/ntdll.dll
>  1 thread 1096.0xc40  0x7c90eb94 in ntdll!LdrAccessResource () from 
>/cygdrive/c/WINDOWS/system32/ntdll.dll
>[Switching to thread 1 (thread 1096.0xc40)]#0  0x7c90eb94 in 
>ntdll!LdrAccessResource () from /cygdrive/c/WINDOWS/system32/ntdll.dll
>#6  0x00000000 in ?? ()
>#0  0x7c90eb94 in ntdll!LdrAccessResource () from 
>/cygdrive/c/WINDOWS/system32/ntdll.dll
>#1  0x7c90e9ab in ntdll!ZwWaitForMultipleObjects () from 
>/cygdrive/c/WINDOWS/system32/ntdll.dll
>#2  0x7c8094e2 in KERNEL32!CreateFileMappingA () from 
>/cygdrive/c/WINDOWS/system32/kernel32.dll
>#3  0x00000002 in ?? ()
>#4  0x0021fe38 in ?? ()
>#5  0x00000001 in ?? ()
>#6  0x00000000 in ?? ()

Try "info threads" and you may see that thread 1 is what you're interested
in.  Windows creates a new thread in the attached process when gdb attaches
to it so this is not what you would normally be interested in.

Note that if the process is stopped in a Windows DLL the stack trace
will probably not be very informative.

cgf

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