From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/14400 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Florian Weimer Newsgroups: gmane.linux.lib.musl.general Subject: Re: [PATCH] Fix the use of sigaltstack to return to the saved main stack. Date: Fri, 12 Jul 2019 11:18:49 +0200 Message-ID: <87h87r391i.fsf@oldenburg2.str.redhat.com> References: <20190709193004.GQ1506@brightrain.aerifal.cx> <20190710183931.GT1506@brightrain.aerifal.cx> <20190710212319.GM21055@port70.net> Reply-To: musl@lists.openwall.com Mime-Version: 1.0 Content-Type: text/plain Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="223769"; mail-complaints-to="usenet@blaine.gmane.org" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.2 (gnu/linux) To: musl@lists.openwall.com Original-X-From: musl-return-14416-gllmg-musl=m.gmane.org@lists.openwall.com Fri Jul 12 11:19:07 2019 Return-path: Envelope-to: gllmg-musl@m.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by blaine.gmane.org with smtp (Exim 4.89) (envelope-from ) id 1hlrhr-000w6m-Bk for gllmg-musl@m.gmane.org; Fri, 12 Jul 2019 11:19:07 +0200 Original-Received: (qmail 1140 invoked by uid 550); 12 Jul 2019 09:19:04 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Original-Received: (qmail 1119 invoked from network); 12 Jul 2019 09:19:03 -0000 In-Reply-To: <20190710212319.GM21055@port70.net> (Szabolcs Nagy's message of "Wed, 10 Jul 2019 23:23:19 +0200") X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.47]); Fri, 12 Jul 2019 09:18:51 +0000 (UTC) Xref: news.gmane.org gmane.linux.lib.musl.general:14400 Archived-At: * Szabolcs Nagy: > the comment does not make sense to me, the check is obviously > not redundant. > > MINSIGSTKSZ is a libc api, has nothing to do with the kernel > > the kernel also defines a MINSIGSZTKSZ but musl is an > abstraction layer higher, the linux limit should not be > observable to users, only the limit defined by musl, > which ensures not only that the kernel can deliver a > signal but also reserves space of any current or future > hackery the c runtime may need to do around signal handling, > so that trivial c language signal handler is guaranteed > to work. Please keep in mind that the kernel stack requirements for delivering a signal vary and tend to increase over time, with newer CPU generations with larger register files. It leads to bugs to pretend this value is constant. Thanks, Florian