Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752200AbdGETRX (ORCPT ); Wed, 5 Jul 2017 15:17:23 -0400 Received: from mail-oi0-f48.google.com ([209.85.218.48]:35863 "EHLO mail-oi0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751772AbdGETRV (ORCPT ); Wed, 5 Jul 2017 15:17:21 -0400 MIME-Version: 1.0 In-Reply-To: <20170705185937.GB24459@1wt.eu> References: <20170704084122.GC14722@dhcp22.suse.cz> <20170704093538.GF14722@dhcp22.suse.cz> <20170704094728.GB22013@1wt.eu> <20170704104211.GG14722@dhcp22.suse.cz> <20170704113611.GA4732@decadent.org.uk> <1499209315.2707.29.camel@decadent.org.uk> <1499257180.2707.34.camel@decadent.org.uk> <20170705185937.GB24459@1wt.eu> From: Linus Torvalds Date: Wed, 5 Jul 2017 12:17:20 -0700 X-Google-Sender-Auth: 5wfc4hiBUeDf1ot6gmcnPc_B3TI Message-ID: Subject: Re: [PATCH] mm: larger stack guard gap, between vmas To: Willy Tarreau Cc: Ben Hutchings , Michal Hocko , Hugh Dickins , Oleg Nesterov , "Jason A. Donenfeld" , Rik van Riel , Larry Woodman , "Kirill A. Shutemov" , Tony Luck , "James E.J. Bottomley" , Helge Diller , James Hogan , Laura Abbott , Greg KH , "security@kernel.org" , Qualys Security Advisory , LKML , Ximin Luo Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 626 Lines: 17 On Wed, Jul 5, 2017 at 11:59 AM, Willy Tarreau wrote: > > Don't you think that the option of having a sysctl to relax the check > per task wouldn't be easier for distros and safer overall ? Ie, emit > a warning the first time the gap is hit instead of segfaulting, then > reduce it to something that used to work (4k or 64k, I don't remember) > and try again ? It used to be just 4k. .. and I think that might be a valid way to find these things, but would it be safer? It basically disables the new stack gap entirely apart from the warning. And maybe that's ok and distros prefer that? Linus