Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754368Ab3JHTU3 (ORCPT ); Tue, 8 Oct 2013 15:20:29 -0400 Received: from mail-vb0-f52.google.com ([209.85.212.52]:50007 "EHLO mail-vb0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752896Ab3JHTU1 (ORCPT ); Tue, 8 Oct 2013 15:20:27 -0400 MIME-Version: 1.0 In-Reply-To: <20131008190523.GW30970@tucnak.zalov.cz> References: <20131005234430.GA22485@localhost> <20131008075151.GA15689@localhost> <20131008185154.GA8258@redhat.com> <20131008190523.GW30970@tucnak.zalov.cz> Date: Tue, 8 Oct 2013 12:20:26 -0700 X-Google-Sender-Auth: 8AHTZk_Gpx_ykYWwr_MEkukWCBQ Message-ID: Subject: Re: [x86] BUG: unable to handle kernel paging request at 00740060 From: Linus Torvalds To: Jakub Jelinek Cc: Oleg Nesterov , Fengguang Wu , Richard Henderson , Peter Zijlstra , Ingo Molnar , Linux Kernel Mailing List Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1249 Lines: 26 On Tue, Oct 8, 2013 at 12:05 PM, Jakub Jelinek wrote: > > If you suspect a compiler bug, can somebody please narrow it down to > a single object file (if I've skimmed the patch right, it is just an > optimization, where object files compiled without and with the patch > should actually coexist fine in the same kernel), ideally to a single > routine if possible and post a preprocessed source + gcc command line > + version of gcc? It is indeed just an optimization, and we could in theory switch between the two versions on a case-by-case basis, but we don't have any sane way to really do that. I'll try to see if I can reproduce this on my hardware (just applying that patch on top of my own tip) and see if I can try to narrow things down. But I looked at the assembly for a couple of files, and it all looked good, and I know this patch works fine for others (ie all the normal -tip testing), so I suspect it's something specific to what Fengguang does. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/