From owner-svn-src-all@freebsd.org Wed Dec 20 19:08:14 2017 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 1EE78E9D6F6; Wed, 20 Dec 2017 19:08:14 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from mail.baldwin.cx (bigwig.baldwin.cx [IPv6:2001:470:1f11:75::1]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id EDA1C7C3F8; Wed, 20 Dec 2017 19:08:13 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from ralph.baldwin.cx (astound-66-234-202-155.ca.astound.net [66.234.202.155]) by mail.baldwin.cx (Postfix) with ESMTPSA id 859CF10A8CC; Wed, 20 Dec 2017 14:08:12 -0500 (EST) From: John Baldwin To: Nathan Whitehorn Cc: David Chisnall , Eugene Grosbein , Konstantin Belousov , Conrad Meyer , src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r326758 - in head/sys/i386: conf include Date: Wed, 20 Dec 2017 11:07:59 -0800 Message-ID: <2357779.RlDvz1mMEe@ralph.baldwin.cx> User-Agent: KMail/4.14.10 (FreeBSD/11.1-STABLE; KDE/4.14.30; amd64; ; ) In-Reply-To: <28f2f06b-dc46-99f1-70be-260bb408c827@freebsd.org> References: <201712110432.vBB4WbnE021090@repo.freebsd.org> <1839614.eNG2DjLqvF@ralph.baldwin.cx> <28f2f06b-dc46-99f1-70be-260bb408c827@freebsd.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.4.3 (mail.baldwin.cx); Wed, 20 Dec 2017 14:08:12 -0500 (EST) X-Virus-Scanned: clamav-milter 0.99.2 at mail.baldwin.cx X-Virus-Status: Clean X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 20 Dec 2017 19:08:14 -0000 On Wednesday, December 20, 2017 10:16:58 AM Nathan Whitehorn wrote: >=20 > On 12/20/17 09:14, John Baldwin wrote: > > On Wednesday, December 20, 2017 09:59:26 AM David Chisnall wrote: > >> On 16 Dec 2017, at 18:05, John Baldwin wrote: > >>> When I build a FreeBSD/mips64 kernel with clang, > >>> _any_ simple NFS op triggers a kernel stack overflow. Kernels co= mpiled > >>> with GCC do not. > >> That is not my experience. I haven=E2=80=99t tried a MIPS64 kerne= l built with clang, but with in-tree gcc I get kernel panics as soon as= I try to use NFS, unless I use Stacey=E2=80=99s patches that increase = the kernel stack size. > > I have primarily been using modern GCC for GCC once that was workin= g, but at > > least when running a MALTA64 kernel under qemu I was not triggering= panics > > even with old GCC. With the in-tree clang 5.0 or with CHERI clang,= just > > doing an 'ls' of a NFS directory or even a tab-complete of a path t= hat > > is on NFS reliably triggers a kernel stack overflow for MALTA64 in = qemu. > > > > With Stacey's kstack pages, a clang kernel does survive, but those = are not > > in stock FreeBSD which is where I have been testing this. > > >=20 > With GCC 4, it takes a little while, but trying to build ports over N= FS=20 > is a sure-fire way to bring down the kernel. I haven't tried any othe= r=20 > compilers. Ah, I have only done things like run binaries over NFS and compile simp= le test programs over NFS with GCC 4 (I do run a gdb binary over NFS again= st itself which probably involves a bit of I/O due to debug symbols, etc. = but still not as onerous as building lots of ports. I cross-build the GDB = on the host due to qemu being too slow). clang insta-panics for even triv= ial things like 'ls' and tab-completion though. It's definitely much worse= than either version of GCC. --=20 John Baldwin