Cyg32 on Win64 fails with stack-protector

Corinna Vinschen
Tue May 29 17:01:00 GMT 2018

Hi Ben,

On Apr 27 19:12, Ben RUBSON wrote:
> Hi,
> We are facing an issue with Cygwin 2.10 32 bits running on Windows 64 bits.
> Issue was found running EncFS FUSE FS using WinFsp.
> When forking, and calling StartServiceCtrlDispatcher, program fails with
> 0xC0000028 / STATUS_BAD_STACK.
> Testing several Cygwin versions reveals that issue was introduced between
> 2017-11-14 and 2017-12-01.
> And Bill (WinFsp author) found that compiling with -fno-stack-protector
> works around the issue.
> There you can then find the full story and Bill's nice investigation :
> Could it be possible something went wrong with Cygwin ?
> Thank you very much for your support !

Even with Bill's additionl info I have no idea what change in the
above time frame might be the culprit, especially since no change
has been made to stack handling.

I suggest to build your own Cygwin and bisect it.  Also, you
may want to run your stuff under GDB and set breakpoints to, e.g.,
Cygwin's exception::handle method.  Make sure the cygwin1.dbg
file can be found by GDB.


Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat
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