cygwin bash crashes on Win Serv 2008

Corinna Vinschen corinna-cygwin@cygwin.com
Thu Oct 23 14:10:00 GMT 2008


On Oct 23 15:54, Corinna Vinschen wrote:
> On Oct 20 14:42, Freddy Jensen wrote:
> > 
> > Apparently the cygwin bash crash on Win Serv 2008 is related to the
> > "Terminal Services" on Windows. It looks like the problem is not
> > there if the Terminal Services has not been installed/started.
> 
> I can confirm this observation.  It doesn't matter if the TS services
> are started or not.  Just by having TS installed, certain Cygwin
> processes crash.  In my case I can observe crashes in bash, grep, and
> GDB, as soon as TS is installed.  However, other applications run fine,
> tcsh, vim, all from coreutils as far as I can see...
> 
> The crashes don't occur in Cygwin, but in the application code.  As I
> said, one of the crashing apps is bash.  I created a full debug bash
> version and a special debug version of GDB which, for some reason, runs
> fine, in contrast to the net release version of GDB.  What happens is
> that some arbitrary application function is called from main() and the
> first instruction in this function is the opcode for storing the frame
> pointer on the stack, `push %ebp'.

I seem to have missed the point here.  The point is, this `push %ebp'
instruction is the one crashing, producing a segmentation violation.

>   This is, in theory, an entirely
> harmless operation.  The stack and register content before and after the
> crash are looking absolutely normal.  The push does neither operate on
> an invalid address nor on a page boundary, nor is it misaligned.  It's
> just a push to some arbitrary address within an existing stack page.
> 
> Another strange effect is that even teeny little changes to the
> application code (adding a `puts("hello");' or something) result in
> entirely different function calls to crash.  The only constant factor is
> that it's always the first assembler instruction in some application
> function.
> 
> For testing I tried to disabled SEH and the Ctrl-C handler in Cygwin,
> but the crashes persist.
> 
> This puzzles me no end.  Here's the only way I found so far to get rid
> of the crashes: Remove Terminal Services and reboot the machine.
> Reinstall TS and you're back to square one.
> 
> 
> Any hints or help to debug this weird phenomenon are gratefully
> appreciated.
> 
> 
> Corinna
> 
> -- 
> Corinna Vinschen                  Please, send mails regarding Cygwin to
> Cygwin Project Co-Leader          cygwin AT cygwin DOT com
> Red Hat
> 
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-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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