Re: cygwin-1.7.10-1 fork - address space needed by ... already in use

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

Hi Denis,

On Mar  5 13:14, Corinna Vinschen wrote:
> On Mar  5 13:02, Denis Excoffier wrote:
> > On Mon, Mar 05, 2012 at 10:59:19AM +0100, Corinna Vinschen wrote:
> > >> On Mar  5 08:09, Denis Excoffier wrote:
> > >> >    947 [main] sh 660! _pinfo::dup_proc_pipe: something failed for pid 0: res 660, hProcess 0x6C8, wr_proc_pipe 0x758 vs. 0x758, Win32 error 5 
> > >> >      2 [main] sh 3360! _pinfo::dup_proc_pipe: something failed for pid 0: res 3360, hProcess 0x6BC, wr_proc_pipe 0x758 vs. 0x758, Win32 error 5 
> > >> >   1345 [main] sh 3772! _pinfo::dup_proc_pipe: something failed for pid 0: res 3772, hProcess 0x6CC, wr_proc_pipe 0x758 vs. 0x758, Win32 error 5 
> > >> > [...]
> > >> 
> > >> Actually, I don't quite understand them.  The pid is apparently not
> > >> initialized yet, at the time the message occurs.  The code in question
> > >> tries to duplicate a pipe handle into another process and fails.  But
> > >> the process handle to the other has been created by this process, so it
> > >> should have all rights to duplicate the handle.  Hmm.  What command
> > >> were you running at the time?  Maybe it is reproducible.
> > You mean, may be it is debuggable?
> > 
> > Please first apply the following, and provide me with further
> > instrumentation in order that i can narrow down the problem when it
> > occurs.
> > 
> > *** winsup0/cygwin/pinfo.cc	Wed Feb 15 15:46:18 2012
> > --- winsup/cygwin/pinfo.cc	Mon Mar  5 12:53:30 2012
> > ***************
> > *** 1001,1007 ****
> >       {
> >         wr_proc_pipe = orig_wr_proc_pipe;
> >         warn_printf ("something failed for pid %d: res %d, hProcess %p, wr_proc_pipe %p vs. %p, %E",
> > ! 		   res, pid, hProcess, wr_proc_pipe, orig_wr_proc_pipe);
> >       }
> >     else
> >       {
> > --- 1001,1007 ----
> >       {
> >         wr_proc_pipe = orig_wr_proc_pipe;
> >         warn_printf ("something failed for pid %d: res %d, hProcess %p, wr_proc_pipe %p vs. %p, %E",
> > ! 		   pid, res, hProcess, wr_proc_pipe, orig_wr_proc_pipe);
> >       }
> >     else
> >       {
> 
> Thanks for catching!  I applied this patch.  So the pids are not wrong,
> after all.  As for debugging, it would be helpful to have a command to
> reproduce it.  I can't tell you off-hand what to hunt for.  This is
> Chris' code, so he probably knows much better what to look for than I do.

can you please test this again using the latest developer snapshot or
the current from CVS if you build Cygwin by yourself?  It provides a bit
more information to find the reason for the permission denied error in
_pinfo::dup_proc_pipe.

In theory, the user should have permissions to duplicate handles into
every own process, if the handle has been opened with these permissions,
so it's quite interesting to find the reason.


Thanks,
Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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