From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 18 Aug 2004 08:36:27 +0200 From: Arjan van de Ven Subject: Re: arch_get_unmapped_area_topdown vs stack reservations Message-ID: <20040818063627.GA31081@devserv.devel.redhat.com> References: <170170000.1092781114@flay> <20040818061121.GB21740@devserv.devel.redhat.com> <259380000.1092809909@[10.10.2.4]> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="pWyiEgJYm5f9v55/" Content-Disposition: inline In-Reply-To: <259380000.1092809909@[10.10.2.4]> Sender: owner-linux-mm@kvack.org Return-Path: To: "Martin J. Bligh" Cc: Ingo Molnar , linux-mm mailing list List-ID: --pWyiEgJYm5f9v55/ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Aug 17, 2004 at 11:18:30PM -0700, Martin J. Bligh wrote: > --Arjan van de Ven wrote (on Wednesday, August 18, 2004 08:11:21 +0200): > > > On Tue, Aug 17, 2004 at 03:18:34PM -0700, Martin J. Bligh wrote: > >> I worry that the current code will allow us to intrude into the > >> reserved stack space with a vma allocation if it's requested at > >> an address too high up. One could argue that they got what they > >> asked for ... but not sure we should be letting them do that? > > > > well even the non-flexmmap code allows this... > > Yeah, wasn't meant as a criticism of the new layout, just a general > improvement, perhaps. > > > what is the problem ? > > Just that if they allocate right up to the stack, we'll go boom shortly > afterwards. I guess the question is ... what exactly are the rules > for stack space reservations? well... unless you have a VERY good reason I would see it as rude to prevent this, I mean, the user *asks* for this address. Posix and co I'm sure don't allow you to deny it unless it's really busy. Or say the user unmaps the stack (after allocating a new one and changing esp).... the kernel then would not allow a new area to be mapped there either.... smells like something the kernel should not enforce to me. --pWyiEgJYm5f9v55/ Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iD8DBQFBIvjqxULwo51rQBIRAlq5AJ4gyTqG1yMVery3UyPxvP2WmopFNgCePkRv ZI6MyDkopTbzKYtRZ4Dk3qU= =Ys2g -----END PGP SIGNATURE----- --pWyiEgJYm5f9v55/-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: aart@kvack.org