Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754434AbdCFQuS (ORCPT ); Mon, 6 Mar 2017 11:50:18 -0500 Received: from mx1.redhat.com ([209.132.183.28]:57696 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752973AbdCFQuL (ORCPT ); Mon, 6 Mar 2017 11:50:11 -0500 Date: Mon, 6 Mar 2017 10:40:08 -0600 From: Josh Poimboeuf To: Daniel J Blueman Cc: Linux Kernel , Ingo Molnar Subject: Re: stack frame unwindind KASAN errors Message-ID: <20170306164008.dgg3xthl2ihsdfnu@treble> References: <20170227154727.lbfvtizqzzybekjz@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.6.0.1 (2016-04-01) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Mon, 06 Mar 2017 16:40:10 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 953 Lines: 30 On Mon, Mar 06, 2017 at 02:52:01PM +0800, Daniel J Blueman wrote: > Thanks Josh! > > With this patch, the KASAN warning still occurs, but at > unwind_get_return_address+0x1d3/0x130 instead; the rest of the trace > is identical. > > (gdb) list *(unwind_get_return_address+0x1d3) > 0xffffffff8112bca3 is in unwind_get_return_address > (./include/linux/compiler.h:243). > 238 }) > 239 > 240 static __always_inline > 241 void __read_once_size(const volatile void *p, void *res, int size) > 242 { > 243 __READ_ONCE_SIZE; Looking deeper, I have an idea about what's going on: https://quora.org/dmesg.txt Each of the warnings seems to show an interrupt happening during an EFI call. I'm guessing EFI modified the frame pointer, at least temporarily, which confused the unwinder :-( Would it be possible for you to test again with 4.10? It has some additional unwinder output which should hopefully confirm my suspicions. -- Josh