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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 D7BBCC3A5A3 for ; Tue, 27 Aug 2019 06:23:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A9AE62186A for ; Tue, 27 Aug 2019 06:23:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=endlessm-com.20150623.gappssmtp.com header.i=@endlessm-com.20150623.gappssmtp.com header.b="KArX4Xqm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727578AbfH0GXv (ORCPT ); Tue, 27 Aug 2019 02:23:51 -0400 Received: from mail-qk1-f174.google.com ([209.85.222.174]:39981 "EHLO mail-qk1-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725879AbfH0GXv (ORCPT ); Tue, 27 Aug 2019 02:23:51 -0400 Received: by mail-qk1-f174.google.com with SMTP id f10so1604300qkg.7 for ; Mon, 26 Aug 2019 23:23:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=endlessm-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=0/hxD6Hr7ptf3a0nm0wbNiKDwCnbC2CQ3RkjlONhTig=; b=KArX4XqmEObsHnaBm4GjJXAaKYPwjDKAogelYpBiv9dFe6ZsED4vHJZhoudhagRq1W 5r8RB28TQGkYfHmdt6aypcTB6kGnkxs9+5gsCwlowKkBHWVzytbsTCdfOsBOh8FpJT4f rh4pKTU95hwocUpqRKimsgOR3E9G+xBFPhlB3iezYeBu/UUO+CG7ODlXN5iESTcbLA0A /QUuUdbjBhrRTXqKkdyy7ndpbSbV1YJyzrfA8ELJPe8zfv7BqKktY+EDY9tdoWHfQYjC 2wcyoOrtbMiP23RnT+T2kIxtSIdgd7H+fZm+oscWtJ5ECPFMfY/YSJm/tHiLoemwmppJ dToQ== 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=0/hxD6Hr7ptf3a0nm0wbNiKDwCnbC2CQ3RkjlONhTig=; b=S65AfhrSkp7zgO8XZLcbAbH9FpQcGxMWhG+1xI6COdZX8QpdtDA7Ea9PoBSMtavmOA TrwU0HdEFodzZW7x+R8pkiCX5mn9vGHnAlH3AX6P2kldPyNOSuOmcVYQKlitUCe3MDbg RN0LqT2lO11ZjmhxB5f0cfHdTx0IIf7QvWdVxUqWW5xtL4c7sOvsM1jjDvfzG5D6M4T7 wMI1tRGKppQihyvl56R0cW09BPEuaNxqGGxktDJmtP1QfDAwm9qBiTPGezYsaQxe9ECM c6I1bJ37vdrpebziXhQiIKYU2oHaDXakkdEMBa7321753y8A4c4gUePdk4Je4l7WwnDT HPqg== X-Gm-Message-State: APjAAAVnJX57jakjXP2mR4/rd9DOpzkg/m1uEF4dFcRsDkAl/H3AszXY gsjJI/yx9jWeoaypPmztaL6u5PCKTCmif4MsP1VXG8nsGDc= X-Google-Smtp-Source: APXvYqym5CmRL8vHwAZrqeyLTETMdDqFYUYLDO9U8NmrNR74AAMhTnAm/keGm3idiJ+yi5+UHPn6k+e3XVxzLhF0Mxc= X-Received: by 2002:a37:4ed3:: with SMTP id c202mr20171340qkb.457.1566887030069; Mon, 26 Aug 2019 23:23:50 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Daniel Drake Date: Tue, 27 Aug 2019 14:23:39 +0800 Message-ID: Subject: Re: Early EFI-related boot freeze in parse_setup_data() To: linux-efi@vger.kernel.org, Linux Kernel , x86@kernel.org Cc: Linux Upstreaming Team Content-Type: text/plain; charset="UTF-8" Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org On Fri, Aug 16, 2019 at 2:14 PM Daniel Drake wrote: > Anyway, the system freeze occurs in parse_setup_data(), specifically: > > data = early_memremap(pa_data, sizeof(*data)); > data_len = data->len + sizeof(struct setup_data); > > Dereferencing data->len causes the system to hang. I presume it > triggers an exception handler due to some kind of invalid memory > access. > > By returning early in that function, boot continues basically fine. So > I could then log the details: pa_data has value 0x892bb018 and > early_memremap returns address 0xffffffffff200018. Accessing just a > single byte at that address causes the system hang. I noticed a complaint about NX in the logs, right where it does the early_memremap of this data (which is now at address 0x893c0018): Notice: NX (Execute Disable) protection missing in CPU! e820: update [mem 0x893c0018-0x893cec57] usable ==> usable e820: update [mem 0x893c0018-0x893cec57] usable ==> usable e820: update [mem 0x893b3018-0x893bf057] usable ==> usable e820: update [mem 0x893b3018-0x893bf057] usable ==> usable Indeed, in the BIOS setup menu, "NX Mode" was Disabled. Setting it to Enabled avoids the hang and Linux boots as normal. Weird! Daniel