Date: Mon, 13 Jul 2009 21:33:51 +0200 From: Tijl Coosemans <tijl@ulyssis.org> To: freebsd-hackers@freebsd.org Cc: Nate Eldredge <neldredge@math.ucsd.edu>, Alan Cox <alc@freebsd.org>, Alexander Best <alexbestms@math.uni-muenster.de> Subject: Re: mmap/munmap with zero length Message-ID: <200907132133.52217.tijl@ulyssis.org> In-Reply-To: <200907131428.08923.jhb@freebsd.org> References: <permail-200907050732251e86ffa8000022a8-a_best01@message-id.uni-muenster.de> <200907131428.08923.jhb@freebsd.org>
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On Monday 13 July 2009 20:28:08 John Baldwin wrote: > On Sunday 05 July 2009 3:32:25 am Alexander Best wrote: >> so mmap differs from the POSIX recommendation right. the malloc.conf >> option seems more like a workaround/hack. imo it's confusing to have >> mmap und munmap deal differently with len=0. being able to >> succesfully alocate memory which cannot be removed doesn't seem >> logical to me. > > This should fix it: > > --- //depot/user/jhb/acpipci/vm/vm_mmap.c > +++ /home/jhb/work/p4/acpipci/vm/vm_mmap.c > @@ -229,7 +229,7 @@ > > fp = NULL; > /* make sure mapping fits into numeric range etc */ > - if ((ssize_t) uap->len < 0 || > + if ((ssize_t) uap->len <= 0 || > ((flags & MAP_ANON) && uap->fd != -1)) > return (EINVAL); Why not "uap->len == 0"? Sizes of 2GiB and more (32bit) shouldn't cause an error.
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