From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.3 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E0831C04EB5 for ; Fri, 7 Feb 2020 15:18:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B4022246C3 for ; Fri, 7 Feb 2020 15:18:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Ijqx7MgM" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727028AbgBGPSb (ORCPT ); Fri, 7 Feb 2020 10:18:31 -0500 Received: from mail-yb1-f196.google.com ([209.85.219.196]:33835 "EHLO mail-yb1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726674AbgBGPSb (ORCPT ); Fri, 7 Feb 2020 10:18:31 -0500 Received: by mail-yb1-f196.google.com with SMTP id w17so1412724ybm.1 for ; Fri, 07 Feb 2020 07:18:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=nFsoOSwL9YbwXaTDXlHQ5VoCRQV0nAn2vPNJKXbJcGU=; b=Ijqx7MgMTJgA2Zs0AZ9OYA7xm0i7YTRtbow5+VmzNbGcNc8adWDbkUIOTp9arzhY58 BOB8I/6z2TQYHdmRB/RIe4WUY2xDd+p+lte9CinqmvkeJDbY7gVZ9aoYnlfxZxpQ1MMf m9ytl7/TkiFvkxx/xWl2zrdW13ZkFMMXtWV5aRz46dDbOv5y0whs7cmc/EBpvu4ZG+Q1 5hnEo3tzAiK2sAkUHy7Yg5dNBapb8j8KSOBL9C7Ozmy4UiSsbLo5fzfs5xDoCL+weMtd 9EAQxLDIIx4BsQhD3ULwgUslYNMWYJAX3RZ0lj+eJFCx6geNNfCJkdoYWFm0GhnvkgA9 q/3Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=nFsoOSwL9YbwXaTDXlHQ5VoCRQV0nAn2vPNJKXbJcGU=; b=N16HHuAXVrBfE/AYFnkZqjdB/nfeym5nGLnTVJ870ZJIl1T1BNUsn3rTwWMWk3AWDF WguO4UD3UZaMsjnz0jtfWkS0rCkftCcQ/PNRF3fcWZQfPW1yegnRSjbNfV1MOvaQb/49 3x4xmnNDmXfQGmW8RerdxSF5PqxiVrHZU03k8yPV6luvVZd2SQ0p8vX4hfzTxJlepHWD p/Os7svTwfI5FcD6ZQCrJIgXR7pvkhjTN12GlyRHRMO9cYpxzevnbnLAWJr77BdOkMk9 Ds/DoaQDuw7FIYMRfmKjEhrCZsKbR09q0+hKnuP2tAAvSaF/THlqf7Mm+Pd4FEhN7Dlw rf+Q== X-Gm-Message-State: APjAAAUE26txBZiIshZFonSxtfHr2p9AUfStE2i8cMIZ9TGaCUrzeI/D t4GlF77aL86JPUydnfkrCK9wQkdlNFJnNXQCo4VqWw== X-Google-Smtp-Source: APXvYqxNNa5WVr6tDVQ5+kY8QCx69tm+gnrj+/GdtvNWv1dsvL/OQIIdovJljB9ggBjXAxC+SpjJMphhUujpYgsgesw= X-Received: by 2002:a25:d9d4:: with SMTP id q203mr9392649ybg.274.1581088709627; Fri, 07 Feb 2020 07:18:29 -0800 (PST) MIME-Version: 1.0 References: <20200207043836.106657-1-edumazet@google.com> <87tv42xxr5.fsf@nanos.tec.linutronix.de> In-Reply-To: <87tv42xxr5.fsf@nanos.tec.linutronix.de> From: Eric Dumazet Date: Fri, 7 Feb 2020 07:18:18 -0800 Message-ID: Subject: Re: [PATCH] x86/traps: do not hash pointers in handle_stack_overflow() To: Thomas Gleixner Cc: Ingo Molnar , linux-kernel , Eric Dumazet , Andy Lutomirski Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 7, 2020 at 6:44 AM Thomas Gleixner wrote: > > Eric Dumazet writes: > > > Mangling stack pointers in handle_stack_overflow() is moot, > > as registers (including RSP/RBP) are clear anyway. > > > > BUG: stack guard page was hit at 0000000063381e80 (stack is > > 000000008edc5696..0000000012256c50) > > To illustrate your argument above it would be useful to provide the post > patch output as well. Unfortunately this KASAN report has no repro yet. I have no idea what triggered the fault ;) > > > kernel stack overflow (double-fault): 0000 [#1] PREEMPT SMP KASAN > > ... > > RSP: 0018:ffffc90002c1ffc0 EFLAGS: 00010802 > > RAX: 1ffff11004a0094c RBX: ffff888025004180 RCX: c9d82d1007bb146c > > RDX: dffffc0000000000 RSI: ffff888025004a40 RDI: ffff888025004180 > > RBP: ffffc90002c201c0 R08: dffffc0000000000 R09: fffffbfff1405915 > > R10: fffffbfff1405915 R11: 0000000000000000 R12: ffff888025004a60 > > R13: ffff888025004a10 R14: c9d82d1007bb146c R15: ffff888025004180 > > ... > > > > Signed-off-by: Eric Dumazet > > Cc: Andy Lutomirski > > --- > > arch/x86/kernel/traps.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c > > index 6ef00eb6fbb925e86109f86845e2b3ccef4023ec..44873df292bd3f9f77bb721c53cb8a1c40994cca 100644 > > --- a/arch/x86/kernel/traps.c > > +++ b/arch/x86/kernel/traps.c > > @@ -296,7 +296,7 @@ __visible void __noreturn handle_stack_overflow(const char *message, > > struct pt_regs *regs, > > unsigned long fault_address) > > { > > - printk(KERN_EMERG "BUG: stack guard page was hit at %p (stack is %p..%p)\n", > > + printk(KERN_EMERG "BUG: stack guard page was hit at %px (stack > > is %px..%px)\n", > > While touching this, can you please switch it to pr_emerg() ? > Sure I will, thanks.