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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_NEOMUTT 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 79718C4646D for ; Fri, 10 Aug 2018 20:44:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2884922428 for ; Fri, 10 Aug 2018 20:44:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2884922428 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727408AbeHJXQU (ORCPT ); Fri, 10 Aug 2018 19:16:20 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:57608 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727182AbeHJXQU (ORCPT ); Fri, 10 Aug 2018 19:16:20 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 8BBF2738EF; Fri, 10 Aug 2018 20:44:52 +0000 (UTC) Received: from treble (ovpn-122-120.rdu2.redhat.com [10.10.122.120]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2F71D215670D; Fri, 10 Aug 2018 20:44:51 +0000 (UTC) Date: Fri, 10 Aug 2018 15:44:49 -0500 From: Josh Poimboeuf To: Torsten Duwe Cc: Will Deacon , Catalin Marinas , Julien Thierry , Steven Rostedt , Ingo Molnar , Ard Biesheuvel , Arnd Bergmann , AKASHI Takahiro , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, live-patching@vger.kernel.org Subject: Re: [PATCH 3/3] arm64: reliable stacktraces Message-ID: <20180810204449.4asgonydn6yfb6kq@treble> References: <20180810160043.9E45568C76@newverein.lst.de> <20180810160311.C988D68CF4@newverein.lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20180810160311.C988D68CF4@newverein.lst.de> User-Agent: NeoMutt/20180716 X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Fri, 10 Aug 2018 20:44:52 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Fri, 10 Aug 2018 20:44:52 +0000 (UTC) for IP:'10.11.54.6' DOMAIN:'int-mx06.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'jpoimboe@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 10, 2018 at 06:03:11PM +0200, Torsten Duwe wrote: > This is more an RFC in the original sense: is this basically > the correct approach? (as I had to tweak the API a bit). > > In particular the code does not detect interrupts and exception > frames, and does not yet check whether the code address is valid. > The latter check would also have to be omitted for the latest frame > on other tasks' stacks. This would require some more tweaking. > > unwind_frame() now reports whether we had to stop normally or due to > an error condition; walk_stackframe() will pass that info. > __save_stack_trace() is used for a start to check the validity of a > frame; maybe save_stack_trace_tsk_reliable() will need its own callback. > > Any comments welcome. > > Signed-off-by: Torsten Duwe Before we do this we'll need the same analysis we did for ppc64le to figure out if objtool is needed. -- Josh