From owner-freebsd-toolchain@freebsd.org Fri May 5 08:23:01 2017 Return-Path: Delivered-To: freebsd-toolchain@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 87354D5E870 for ; Fri, 5 May 2017 08:23:01 +0000 (UTC) (envelope-from markmi@dsl-only.net) Received: from asp.reflexion.net (outbound-mail-210-77.reflexion.net [208.70.210.77]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 39133A2E for ; Fri, 5 May 2017 08:23:00 +0000 (UTC) (envelope-from markmi@dsl-only.net) Received: (qmail 2159 invoked from network); 5 May 2017 08:26:18 -0000 Received: from unknown (HELO mail-cs-01.app.dca.reflexion.local) (10.81.19.1) by 0 (rfx-qmail) with SMTP; 5 May 2017 08:26:18 -0000 Received: by mail-cs-01.app.dca.reflexion.local (Reflexion email security v8.40.0) with SMTP; Fri, 05 May 2017 04:22:59 -0400 (EDT) Received: (qmail 21919 invoked from network); 5 May 2017 08:22:58 -0000 Received: from unknown (HELO iron2.pdx.net) (69.64.224.71) by 0 (rfx-qmail) with (AES256-SHA encrypted) SMTP; 5 May 2017 08:22:58 -0000 Received: from [192.168.1.106] (c-76-115-7-162.hsd1.or.comcast.net [76.115.7.162]) by iron2.pdx.net (Postfix) with ESMTPSA id 4EE72EC7ED9; Fri, 5 May 2017 01:22:58 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 10.3 \(3273\)) Subject: Re: llvm FreeBSD powerpc ABI target bug fix: Re: [Bug 26519] Clang 4.0.0's "Target: powerpc-unknown-freebsd11.0" code generation is violating the SVR4 ABI (SEGV can result) From: Mark Millard In-Reply-To: <8F708AD1-055E-41BD-BD92-6A87C5FBAA60@dsl-only.net> Date: Fri, 5 May 2017 01:22:57 -0700 Cc: FreeBSD Toolchain , Dimitry Andric Content-Transfer-Encoding: quoted-printable Message-Id: <78CD5050-2B2B-4213-AF11-7EF744F608B2@dsl-only.net> References: <0103401A-CEEA-4992-A45E-E60EA151119B@dsl-only.net> <893ECA11-7C80-4D24-A496-92ADC7978A07@FreeBSD.org> <8F708AD1-055E-41BD-BD92-6A87C5FBAA60@dsl-only.net> To: FreeBSD PowerPC ML X-Mailer: Apple Mail (2.3273) X-BeenThere: freebsd-toolchain@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Maintenance of FreeBSD's integrated toolchain List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 05 May 2017 08:23:01 -0000 On 2017-May-5, at 12:45 AM, Mark Millard wrote: > On 2017-May-4, at 2:41 PM, Dimitry Andric wrote: >=20 >> . . . >> Thanks for the notice. I have merged the upstream fix into head in >> r317810, and I will MFC it after a few days. >=20 > I now have an old PowerMac running: >=20 > # uname -paKU > FreeBSD FBSDG4S 12.0-CURRENT FreeBSD 12.0-CURRENT r317820M powerpc = powerpc 1200030 1200030 >=20 > where buildworld was via clang 4 (an amd64->powerpc > cross build). Even the classic tiny program that > previously showed C++ exception handling was broken > and would crash the program now works when > re-compiled and re-linked. Commands that were > previous broken now work. >=20 > (But my testing is nearly minimal at this point.) >=20 > The kernel is from gcc421. >=20 >=20 >=20 > I did try booting a kernel built by system-clang 4 > and it got to: >=20 > exec /sbin/init: error 13 >=20 > and a later alignment exception at sf_buf_alloc+0x260 >=20 > (Hand transcribed screen information.) >=20 > This is the same as the last time that I tried > such. The exception involved: >=20 > exec_map_first_page > kern_execve > sys_execve > start_init > fork_exit > fork_trampoline >=20 >=20 >=20 > For the gcc 4.2.1 based kernel boot I have > had one odd fatal kernel trap (0x903a64a, > "unknown") where the lr showed 0x907f . It > reported being stopped at: >=20 > ffs_truncate+0x1080 >=20 > It appears that "call doadump" worked but > I've not looked at what was put in > /var/crash/ . If I leave the PowerMac idle running: # uname -paKU FreeBSD FBSDG4S 12.0-CURRENT FreeBSD 12.0-CURRENT r317820M powerpc = powerpc 1200030 1200030 it eventually gets the same ffs_truncate-tied fatal kernel trap, with the same odd lr and the like. So, while I cannot directly cause the problem at a specific time, the problem is repeatable. I did not build the kernel with a so-called "red-zone" to work around any stack-operation ordering problems that might still be around. But I do not know that such is involved here. It may be a while before I manage to get that much of an analysis done. =3D=3D=3D Mark Millard markmi at dsl-only.net