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=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 C89C9C38A2A for ; Mon, 11 May 2020 00:50:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A3C91206D6 for ; Mon, 11 May 2020 00:50:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729388AbgEKAu3 (ORCPT ); Sun, 10 May 2020 20:50:29 -0400 Received: from mga01.intel.com ([192.55.52.88]:49691 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729095AbgEKAu2 (ORCPT ); Sun, 10 May 2020 20:50:28 -0400 IronPort-SDR: Y2L6yXiv3EE+O9ZJQv8YQ+9IqpsyuvNnSMoDl1S+AyDXlffwn9koFaIuNHx6n0mmLqT8IYEUG+ 7LvpLpbIbaaA== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 May 2020 17:50:28 -0700 IronPort-SDR: jBNw3LvyTYq9CTX3yjVAc8sa/ZR6hJ4vMGpoNTS80+685W83DLQYRP9A4zrnt4/ahijke6PhDn VMSo7FveWRgw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,377,1583222400"; d="scan'208";a="463204297" Received: from tassilo.jf.intel.com (HELO tassilo.localdomain) ([10.7.201.21]) by fmsmga006.fm.intel.com with ESMTP; 10 May 2020 17:50:28 -0700 Received: by tassilo.localdomain (Postfix, from userid 1000) id 72A19301C52; Sun, 10 May 2020 17:50:28 -0700 (PDT) Date: Sun, 10 May 2020 17:50:28 -0700 From: Andi Kleen To: Vegard Nossum Cc: Sasha Levin , linux-kernel@vger.kernel.org, tglx@linutronix.de, luto@kernel.org, tony.luck@intel.com, chang.seok.bae@intel.com Subject: Re: [PATCH v10 00/18] Enable FSGSBASE instructions Message-ID: <20200511005028.GA226400@tassilo.jf.intel.com> References: <20200423232207.5797-1-sashal@kernel.org> <5a6a0ef5-4dfc-d0b1-9181-5df4211cfcd9@oracle.com> <20200511004842.GJ3538@tassilo.jf.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200511004842.GJ3538@tassilo.jf.intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > So this is a check that checks if you're running in user mode if > you have a debug trap with single step, but somehow it triggered > for a user segment. > > Probably the regs got corrupted. > > Sasha, I suspect you're missing a mov %rsp,%rdi somewhere in the > debug entry path that sets up the regs argument for the C code. ... Ah never mind. Thomas has a better explanation. -Andi