Date: Fri, 21 May 2021 15:15:43 +0100 From: Jessica Clarke <jrtc27@freebsd.org> To: Marcin Wojtas <mw@semihalf.com> Cc: 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: <02078965-24BE-4F23-92D5-5E8E54A0C3E7@freebsd.org> In-Reply-To: <CAPv3WKeV1Oz8Gbv0LBFD03J6k3k%2B2XMBEvi28DuMM8LVq8cjrQ@mail.gmail.com> References: <202105211334.14LDYqoa004343@gitrepo.freebsd.org> <04F25FD0-7863-4AC1-A257-EF0F1EB90659@freebsd.org> <CAPv3WKeV1Oz8Gbv0LBFD03J6k3k%2B2XMBEvi28DuMM8LVq8cjrQ@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
> On 21 May 2021, at 15:11, Marcin Wojtas <mw@semihalf.com> wrote: >=20 > Hi Jess >=20 > pt., 21 maj 2021 o 15:39 Jessica Clarke <jrtc27@freebsd.org> = napisa=C5=82(a): >>=20 >> On 21 May 2021, at 14:34, Marcin Wojtas <mw@FreeBSD.org> wrote: >>>=20 >>> The branch main has been updated by mw: >>>=20 >>> URL: = https://cgit.FreeBSD.org/src/commit/?id=3Daf949c590bd8a00a5973b5875d7e0fa6= 832ea64a >>>=20 >>> 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 >>>=20 >>> Disable stack gap for ntpd during build. >>>=20 >>> 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. >>=20 >> Isn=E2=80=99t the bug that the unusable gap counts as usage? >>=20 >> Jess >>=20 >=20 > 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=E2=80=99s my point, there is nothing to =E2=80=9Cfix=E2=80=9D = upstream. NTPD uses less than 200K of stack, thus it is perfectly reasonable for it to set its limit to = that. The 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=E2=80=99s entirely = unreasonable for applications to have to account for that. Jess
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?02078965-24BE-4F23-92D5-5E8E54A0C3E7>