From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 22827 invoked by alias); 21 Jul 2012 02:58:58 -0000 Received: (qmail 22819 invoked by uid 22791); 21 Jul 2012 02:58:57 -0000 X-SWARE-Spam-Status: No, hits=-4.0 required=5.0 tests=AWL,BAYES_00,KHOP_RCVD_UNTRUST,KHOP_THREADED,RCVD_IN_HOSTKARMA_W,RCVD_IN_HOSTKARMA_WL X-Spam-Check-By: sourceware.org Received: from imr3.ericy.com (HELO imr3.ericy.com) (198.24.6.13) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Sat, 21 Jul 2012 02:58:43 +0000 Received: from eusaamw0707.eamcs.ericsson.se ([147.117.20.32]) by imr3.ericy.com (8.13.8/8.13.8) with ESMTP id q6L2weIc020344 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=FAIL); Fri, 20 Jul 2012 21:58:40 -0500 Received: from EUSAACMS0703.eamcs.ericsson.se ([169.254.1.11]) by eusaamw0707.eamcs.ericsson.se ([147.117.20.32]) with mapi; Fri, 20 Jul 2012 22:58:39 -0400 From: Marc Khouzam To: Jan Kratochvil , "gdb-patches@sourceware.org" Date: Sat, 21 Jul 2012 02:58:00 -0000 Subject: RE: [patch] ON_STACK: Warn on buggy Linux i386 kernels Message-ID: References: <20120703142709.GA21059@host2.jankratochvil.net> In-Reply-To: <20120703142709.GA21059@host2.jankratochvil.net> Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-IsSubscribed: yes 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: 2012-07/txt/msg00417.txt.bz2 > ________________________________________ > From: Jan Kratochvil [jan.kratochvil@redhat.com] > Sent: July 3, 2012 10:27 AM > To: gdb-patches@sourceware.org > Subject: [patch] ON_STACK: Warn on buggy Linux i386 kernels >=20 > Hi, >=20 > as discussed in: > Possible future NX ON_STACk regression Re: [patch 3/3] Use ON_STA= CK for i386/amd64 (gdb2495.exp regression) > http://sourceware.org/ml/gdb-patches/2012-06/msg00568.html >=20 > I have found the problem with ON_STACK inferior calls affects only i386 L= inux > kernels (not x86_64, nor Fedora i386 PAE). It was fixed/removed in Fedor= a by > commit 88fa1f0332d188795ed73d7ac2b1564e11a0b4cd > Author: Dave Jones > Date: Mon Jun 4 11:56:08 2012 -0400 > disable 32bit nx, it seems to be broken > http://pkgs.fedoraproject.org/gitweb/?p=3Dkernel.git;a=3Dcommitdi= ff;h=3D88fa1f0332d188795ed73d7ac2b1564e11a0b4cd > http://pkgs.fedoraproject.org/gitweb/?p=3Dkernel.git;a=3Dblob_pla= in;f=3Dlinux-2.6-32bit-mmap-exec-randomization.patch;hb=3D88fa1f0332d188795= ed73d7ac2b1564e11a0b4cd > http://pkgs.fedoraproject.org/gitweb/?p=3Dkernel.git;a=3Dblob_pla= in;f=3Dlinux-2.6-i386-nx-emulation.patch;hb=3D88fa1f0332d188795ed73d7ac2b15= 64e11a0b4cd > http://pkgs.fedoraproject.org/gitweb/?p=3Dkernel.git;a=3Dblob_pla= in;f=3Dnx-emu-remove-cpuinitdata-for-disable_nx-on-x86_32.patch;hb=3D88fa1f= 0332d188795ed73d7ac2b1564e11a0b4cd > http://pkgs.fedoraproject.org/gitweb/?p=3Dkernel.git;a=3Dblob_pla= in;f=3Dshlib_base_randomize.patch;hb=3D88fa1f0332d188795ed73d7ac2b1564e11a0= b4cd > So the last Fedora kernel where it was reproducible is: kernel-3.4.0-1.fc= 17.i686 >=20 > It does not seem to be ever present in upstream ("vanilla") Linux kernels. >=20 > But I have found ubuntu-12.04-dvd-i386.iso (both GA and latest updates) w= hich > is LTS (=3Dstill maintained) is also affected by this problem so I expect= there > maybe vocal feedback. That's me :) I'm seeing this warning. IIUC I can safely ignore this warnin= g? The warning is pretty intimidating: (gdb) run Starting program: myapp.exe=20 warning: Cannot call inferior functions, you have broken Linux kernel i386= NX (non-executable pages) support! Thanks for having investigated this. Marc > It puts there only a warning. As it is both off-trunk patch and also the > patch is present in neither old or new (at least Fedora) kernels and as it > does not affect the most basic debugging I did not find it worth a workar= ound. > Rather Ubuntu should provide a fix IMO. >=20 >=20 > Thanks, > Jan