A vexing installation problem

Christopher Faylor cgf-no-personal-reply-please@cygwin.com
Thu Dec 30 23:23:00 GMT 2004

On Thu, Dec 30, 2004 at 03:15:22PM -0800, David Hinds wrote:
>On Thu, 2 Dec 2004 at 09:36:21 AM -0500, Christopher Faylor wrote:
>> Could you try running this under gdb to see if you get more of a clue
>> about where cygwin is dying?  The last entry in the snapshot is not
>> necessarily indicative of this.
>[ recap: my problem is that on a dual Xeon workstation running XP SP2,
>  loading cygwin1.dll seems to crash out with a segfault about 99% of
>  the time, but once I can get an instance of any cygwin program going,
>  everything works fine after that ]
>I've finally gotten a chance to look at this again.  I downloaded the
>current snapshot (cygwin-inst-20041227) and tried running 'mount' from
>that package under gdb.  The backtrace does not seem helpful, however:
>> (gdb) run
>> Starting program: /c/scratch/usr/bin/mount.exe
>> Program received signal SIGSEGV, Segmentation fault.
>> [Switching to thread 5496.0x15e8]
>> 0x7c810858 in KERNEL32!CreateThread () from /c/WINDOWS/system32/kernel32.dll
>> (gdb) backtrace
>> #0  0x7c810858 in KERNEL32!CreateThread ()
>>    from /c/WINDOWS/system32/kernel32.dll

It seems like you only followed some of my instructions:

  To debug cygwin:
  1) Put the latest version of the dll which works for you
     in a directory "foo" along with a copy of gdb.exe.

  2) Set the environment variable CYGWIN_TESTING=1 at the windows

  3) Debug a cygwin application by typing:

     c:\foo\gdb /bin/pwd

     (do not cd to the foo directory here)

  4) Type "run".

  5) If you get a SEGV, it is possible that it is just a natural occurrence
     of calling BadWritePtr.  Type 'continue' a few times to make sure that
     the SEGV address does not change.

  6) Type "backtrace" and report the results here.

You missed step 5, apparently.


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