From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 14782 invoked by alias); 22 Nov 2008 15:31:37 -0000 Received: (qmail 14767 invoked by uid 22791); 22 Nov 2008 15:31:36 -0000 X-Spam-Check-By: sourceware.org Received: from mtagate8.de.ibm.com (HELO mtagate8.de.ibm.com) (195.212.29.157) by sourceware.org (qpsmtpd/0.31) with ESMTP; Sat, 22 Nov 2008 15:30:39 +0000 Received: from d12nrmr1607.megacenter.de.ibm.com (d12nrmr1607.megacenter.de.ibm.com [9.149.167.49]) by mtagate8.de.ibm.com (8.13.8/8.13.8) with ESMTP id mAMFUakf322302 for ; Sat, 22 Nov 2008 15:30:36 GMT Received: from d12av02.megacenter.de.ibm.com (d12av02.megacenter.de.ibm.com [9.149.165.228]) by d12nrmr1607.megacenter.de.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id mAMFUaIm4362424 for ; Sat, 22 Nov 2008 16:30:36 +0100 Received: from d12av02.megacenter.de.ibm.com (loopback [127.0.0.1]) by d12av02.megacenter.de.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id mAMFUaKD026333 for ; Sat, 22 Nov 2008 16:30:36 +0100 Received: from tuxmaker.boeblingen.de.ibm.com (tuxmaker.boeblingen.de.ibm.com [9.152.85.9]) by d12av02.megacenter.de.ibm.com (8.12.11.20060308/8.12.11) with SMTP id mAMFUawt026327; Sat, 22 Nov 2008 16:30:36 +0100 Message-Id: <200811221530.mAMFUawt026327@d12av02.megacenter.de.ibm.com> Received: by tuxmaker.boeblingen.de.ibm.com (sSMTP sendmail emulation); Sat, 22 Nov 2008 16:30:36 +0100 Subject: Re: [rfc] Handle broken CFI for signal trampolines in libc on amd64-linux To: mark.kettenis@xs4all.nl (Mark Kettenis) Date: Sat, 22 Nov 2008 23:56:00 -0000 From: "Ulrich Weigand" Cc: gdb-patches@sourceware.org In-Reply-To: <11706.86.86.3.213.1227267599.squirrel@webmail.xs4all.nl> from "Mark Kettenis" at Nov 21, 2008 12:39:59 PM X-Mailer: ELM [version 2.5 PL2] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2008-11/txt/msg00608.txt.bz2 Mark Kettenis wrote: > > On Fri, Nov 21, 2008 at 02:33:29AM +0100, Ulrich Weigand wrote: > > > Anyway, while it is certainly good that this is fixed, I'm still > > > wondering why we should rely on that when we have a hard-coded > > > sigtramp detector that should be working just fine under any > > > circumstances. > > > > I think that one reason was the extra work of the signal handler > > sniffer. The amd64 one doesn't do much for named functions, though, > > and functions with CFI are likely to be named. I suggest asking > > Mark Kettenis's opinion. > > My memory is a bit hazy on this, but I think the idea was that the signal > frame unwinder would only be used for older versions of linux/glibc that > don't provide the necessary CFI, and that newer versions would provide > correct CFI which would give the kernel/glibc people complete freedom on > how to implement signal frames. As such, I'm inclined to say "no" to your > diff. OK, fair enough. As the bug is really in my copy of glibc anyway, I'll withdraw my patch. Bye, Ulrich -- Dr. Ulrich Weigand GNU Toolchain for Linux on System z and Cell BE Ulrich.Weigand@de.ibm.com