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=-1.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 58A06C0044C for ; Thu, 1 Nov 2018 10:13:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EC7AC20820 for ; Thu, 1 Nov 2018 10:13:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="LTnaAUk3" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EC7AC20820 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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 S1727821AbeKATQL (ORCPT ); Thu, 1 Nov 2018 15:16:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:47606 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727453AbeKATQL (ORCPT ); Thu, 1 Nov 2018 15:16:11 -0400 Received: from devbox (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 47CD92081B; Thu, 1 Nov 2018 10:13:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1541067231; bh=4f9/JYwKkffXHyozI8uwla/glWKAImJE1/DU/Q3rfIM=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=LTnaAUk3XO8PkjGHPnsRZUSCJTOluYMg5zRBoZMYw1dMaa3EillbsV+q/7iczXNAE +AJfIf4R/mAJVYk2R+9iyOnyrfiT4CWn6tgmlsf5A9s+6OIErOY3hdYG7SQ+m7xiN5 3+696RI5SqM8MwqfEc6En91gnrK2f4AmnaypBOrY= Date: Thu, 1 Nov 2018 19:13:47 +0900 From: Masami Hiramatsu To: Aleksa Sarai Cc: Steven Rostedt , Masami Hiramatsu , "Naveen N. Rao" , Anil S Keshavamurthy , "David S. Miller" , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Brendan Gregg , Christian Brauner , Aleksa Sarai , linux-kernel@vger.kernel.org Subject: Re: [PATCH] kretprobe: produce sane stack traces Message-Id: <20181101191347.74eadff4a5d1fab2d79d7efe@kernel.org> In-Reply-To: <20181031133912.3j5tryq2vyhkdn4d@yavin> References: <20181026132210.12569-1-cyphar@cyphar.com> <20181030101206.2e5998ca3c75496c91ba5b09@kernel.org> <20181031090317.4e211fdd@vmware.local.home> <20181031133912.3j5tryq2vyhkdn4d@yavin> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 1 Nov 2018 00:39:12 +1100 Aleksa Sarai wrote: > On 2018-10-31, Steven Rostedt wrote: > > > Anyway, until that merge happens, this patch looks good to avoid > > > this issue for generic solution (e.g. for the arch which doesn't > > > supports retstack). > > > > I think its time to come up with an algorithm that makes function graph > > work with multiple users, and have kretprobes be able to hook into it > > just like kprobes hooks into function tracer. > > > > I have some ideas on how to get this done, and will try to have an RFC > > patch set ready by plumbers. > > Should I continue working on this patchset? Yes, until we finally introduce Steven's algorithm on all arch (yeah, we still have some archs which don't support graph-tracer but supports kprobes), I think your patch is the best fix for this issue. Thank you, -- Masami Hiramatsu