Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754959AbcKBOys (ORCPT ); Wed, 2 Nov 2016 10:54:48 -0400 Received: from mail-oi0-f68.google.com ([209.85.218.68]:35006 "EHLO mail-oi0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753531AbcKBOyo (ORCPT ); Wed, 2 Nov 2016 10:54:44 -0400 MIME-Version: 1.0 In-Reply-To: <201611021950.FEJ34368.HFFJOOMLtQOVSF@I-love.SAKURA.ne.jp> References: <201611012336.IAC18714.VLMOQSHOFtOFJF@I-love.SAKURA.ne.jp> <201611021950.FEJ34368.HFFJOOMLtQOVSF@I-love.SAKURA.ne.jp> From: Linus Torvalds Date: Wed, 2 Nov 2016 08:54:43 -0600 X-Google-Sender-Auth: fIkb6UMqIxoPvWZ7Ig9OyDcIVsM Message-ID: Subject: Re: [4.9-rc3] BUG: unable to handle kernel paging request at ffffc900144dfc60 To: Tetsuo Handa Cc: Peter Zijlstra , Ingo Molnar , Andrew Lutomirski , "the arch/x86 maintainers" , Linux Kernel Mailing List , Brian Gerst , Borislav Petkov , Jann Horn , Linux API , Kees Cook , Tycho Andersen 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: 638 Lines: 18 On Wed, Nov 2, 2016 at 4:50 AM, Tetsuo Handa wrote: >> >> So I _think_ the fix is to just remove this. Perhaps something like >> the attached? Adding scheduler people since this is in their code.. > > That is not sufficient, for another Oops occurs inside stack_not_used(). > Since I don't want to break stack_not_used(), can we tolerate nested > try_get_task_stack() usage and protect the whole sched_show_task()? Sure, looks good to me. But as Andy says, we should probably apply my patch too, just to get rid of the useless hex printk and the ugly ifdeffery. PeterZ/Ingo? Linus