Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752146AbdL0SKB (ORCPT ); Wed, 27 Dec 2017 13:10:01 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:60321 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751781AbdL0SKA (ORCPT ); Wed, 27 Dec 2017 13:10:00 -0500 Date: Wed, 27 Dec 2017 19:09:56 +0100 (CET) From: Thomas Gleixner To: Andrey Ryabinin cc: Andy Lutomirski , Jakub Kicinski , Ingo Molnar , LKML Subject: Re: linux/master crashes on boot with KASAN=y In-Reply-To: Message-ID: References: <20171223000143.0af3366d@cakuba.netronome.com> <41c68406-ad05-1db7-b0dd-a2e616448ee1@virtuozzo.com> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 919 Lines: 23 On Tue, 26 Dec 2017, Andrey Ryabinin wrote: > On 12/24/2017 04:48 AM, Andy Lutomirski wrote: > > Could this be #define MODULES_END KASAN_ROUND_DOWN(__fix_to_virt(...)) instead? > > > Actually, we could simply set fixed MODULES_END, as it was before > f06bdd4001c2 ("x86/mm: Adapt MODULES_END based on fixmap section size"). > AFAICS, the whole point of f06bdd4001c2 was to move MODULES_END down if > NR_CPUS is big. But since 92a0f81d8957 ("x86/cpu_entry_area: Move it out > of the fixmap") cpu_entry_area is not in fixmap anymore. So it should be > fine to set fixed MODULES_END. > > The only concern I have is 4.14 stable, where 21506525f ("x86/kasan/64: > Teach KASAN about the cpu_entry_area") was backported. Is 92a0f81d8957 > ("x86/cpu_entry_area: Move it out of the fixmap") also a candidate for > stable? > > If so, fixed MODULES_END seems like a better choice. Yes, it's on the way there. Thanks, tglx