Date: Fri, 21 May 2021 07:46:08 -0700 From: Cy Schubert <Cy.Schubert@cschubert.com> To: Jessica Clarke <jrtc27@freebsd.org> Cc: Marcin Wojtas <mw@semihalf.com>, shawn.webb@hardenedbsd.org, Marcin Wojtas <mw@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org>, "dev-commits-src-all@freebsd.org" <dev-commits-src-all@freebsd.org>, "dev-commits-src-main@freebsd.org" <dev-commits-src-main@freebsd.org> Subject: Re: git: af949c590bd8 - main - Disable stack gap for ntpd during build. Message-ID: <202105211446.14LEk8kZ009266@slippy.cwsent.com> In-Reply-To: <02078965-24BE-4F23-92D5-5E8E54A0C3E7@freebsd.org> References: <202105211334.14LDYqoa004343@gitrepo.freebsd.org> <04F25FD0-7863-4AC1-A257-EF0F1EB90659@freebsd.org> <CAPv3WKeV1Oz8Gbv0LBFD03J6k3k%2B2XMBEvi28DuMM8LVq8cjrQ@mail.gmail.com> <02078965-24BE-4F23-92D5-5E8E54A0C3E7@freebsd.org>
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In message <02078965-24BE-4F23-92D5-5E8E54A0C3E7@freebsd.org>, Jessica Clarke w rites: > > On 21 May 2021, at 15:11, Marcin Wojtas <mw@semihalf.com> wrote: > > > > Hi Jess > > > > pt., 21 maj 2021 o 15:39 Jessica Clarke <jrtc27@freebsd.org> napisał(a): > >> > >> On 21 May 2021, at 14:34, Marcin Wojtas <mw@FreeBSD.org> wrote: > >>> > >>> The branch main has been updated by mw: > >>> > >>> URL: https://cgit.FreeBSD.org/src/commit/?id=af949c590bd8a00a5973b5875d7e > 0fa6832ea64a > >>> > >>> commit af949c590bd8a00a5973b5875d7e0fa6832ea64a > >>> Author: Marcin Wojtas <mw@FreeBSD.org> > >>> AuthorDate: 2021-05-21 09:29:22 +0000 > >>> Commit: Marcin Wojtas <mw@FreeBSD.org> > >>> CommitDate: 2021-05-21 13:33:06 +0000 > >>> > >>> Disable stack gap for ntpd during build. > >>> > >>> When starting, ntpd calls setrlimit(2) to limit maximum size of its > >>> stack. The stack limit chosen by ntpd is 200K, so when stack gap > >>> is enabled, the stack gap is larger than this limit, which results > >>> in ntpd crashing. > >> > >> Isn’t the bug that the unusable gap counts as usage? > >> > >> Jess > >> > > > > An alternative solution was submitted > > (https://reviews.freebsd.org/D29832), so that to extend the limit for > > ntpd, but eventually it was recommended to simple disable the stack > > gap for it until it's fixed upstream (see the last comment in the > > linked revision). > > That’s my point, there is nothing to “fix” upstream. NTPD uses less tha > n 200K > of stack, thus it is perfectly reasonable for it to set its limit to that. Th > e > fact that FreeBSD decides to count an arbitrary, non-deterministic amount of > additional unusable virtual address space towards that limit is not its fault > , > but a bug in FreeBSD that needs to be fixed as it’s entirely unreasonable f > or > applications to have to account for that. This latest problem is not stack gap. It is PIE. -- Cheers, Cy Schubert <Cy.Schubert@cschubert.com> FreeBSD UNIX: <cy@FreeBSD.org> Web: https://FreeBSD.org NTP: <cy@nwtime.org> Web: https://nwtime.org The need of the many outweighs the greed of the few.
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