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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 34B39CA9EB9 for ; Wed, 23 Oct 2019 18:31:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ECEBB2173B for ; Wed, 23 Oct 2019 18:31:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="rsvCoTqT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389742AbfJWSbp (ORCPT ); Wed, 23 Oct 2019 14:31:45 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:53762 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726506AbfJWSbp (ORCPT ); Wed, 23 Oct 2019 14:31:45 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=t1mBW2Y77bGoe4WyUZsFuThZaILNwh36eHCTT5RAVak=; b=rsvCoTqTHI+J3MI9MkOQOuOnF 9s0u54rool374MNQEGYKvm4GADQMerw1aowjTT9z4cJVLlP9M+7ubDgkjOKG3A4f4miNHqEnZR+b5 w+pQEWhVSDKbGJGys2SQr43YskveRg0rKJ502puTLy6198xk52XF7mGsso6ce6A0pX9zfsScIIjPr LZwJdLVabsvUIaFstToI3hMaNptxoNtmGoNwMhhgc7UngsgbGfXYQxTQItoKDFZmcnnlt1tQVuIn+ VVpbzWMmnt/u9zjiy5p6fGye2pjOr90jN18a90Z7dGRpA9zwO+Xk+ekinkSxUcuGQIWWbqLahGxTr nXKNYoLjg==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1iNLQ4-0000bL-Bt; Wed, 23 Oct 2019 18:31:40 +0000 Date: Wed, 23 Oct 2019 11:31:40 -0700 From: Matthew Wilcox To: Thomas Gleixner Cc: Cyrill Gorcunov , LKML , Ingo Molnar , Peter Zijlstra , linux-mm@kvack.org, Catalin Marinas , x86@kernel.org, Josh Poimboeuf Subject: Re: [PATCH] x86/dumpstack/64: Don't evaluate exception stacks before setup Message-ID: <20191023183140.GC2963@bombadil.infradead.org> References: <20191019114421.GK9698@uranus.lan> <20191022142325.GD12121@uranus.lan> <20191022145619.GE12121@uranus.lan> <20191023135943.GK12121@uranus.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 23, 2019 at 08:05:49PM +0200, Thomas Gleixner wrote: > Prevent this by checking the validity of the cea_exception_stack base > address and bailing out if it is zero. Could also initialise cea_exception_stack to -1? That would lead to it being caught by ... > end = begin + sizeof(struct cea_exception_stacks); > /* Bail if @stack is outside the exception stack area. */ > if (stk < begin || stk >= end) this existing check.