This is the mail archive of the cygwin mailing list for the Cygwin project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: mmap bug on Windows 9x


On Jul 16 09:12, Anton Ertl wrote:
> Anton Ertl wrote:
> > 
> > On Windows 9x/ME different calls to mmap sometimes produce the same
> > address (without that memory being unmapped in the meantime, at least
> > not by application code).
> 
> You find a condensed test program below.
> 
> On Windows ME with cygwin1.dll 1.5.10 it outputs:
> 
> try mmap($0, $40000, ..., MAP_ANON, ...); success, address=$833ca000
> try mmap($8340b000, $40000, ..., MAP_ANON, ...); success, address=$833ca000
> 
> Note that the result addresses are the same.

Thanks for the testcase!  Wow, I'm impressed.  Three serious bug reports
in two days which all had a simple testcase(tm) attached! 

*Sob*, I'm moved to tears.

Anyway, I found the cause of that problem.  For some reason (moon phase
or so) the mmap code didn't marked pages as used when running under 9x/Me.
This could only be observed under a specific condition of mmapping
anonymous private pages.

I've applied a fix to the repository.  Should be in the next developers
snapshot from http://cygwin.com/snapshots/


Thanks for the report,
Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Co-Project Leader          mailto:cygwin@cygwin.com
Red Hat, Inc.

--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Problem reports:       http://cygwin.com/problems.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]