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=-6.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,NICE_REPLY_A, 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 A52FDC433E2 for ; Tue, 8 Sep 2020 02:55:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 61F2C21481 for ; Tue, 8 Sep 2020 02:55:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599533737; bh=JWnIjcnJzQwoUBMp2JNF74qQ2x9XJSOCWBezRJosGWI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=mMkk8jsy2YvkIpiI+ZBqF7lJUHJG+9pvymRrVKmDo2yDy1AHoUGIEZMrq0jj3u/V9 goX9ZRhHQGEyk64USMTjEA9eGEJqqehHDH6XDBGygurbDFQ7in37yqUom3+MeB1Fz2 ++pahkdcTK9nTqWTyOV38zFTdSPvuxquqDri7gkg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728339AbgIHCzf (ORCPT ); Mon, 7 Sep 2020 22:55:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:60652 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728241AbgIHCze (ORCPT ); Mon, 7 Sep 2020 22:55:34 -0400 Received: from devnote2 (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 03B3720678; Tue, 8 Sep 2020 02:55:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599533733; bh=JWnIjcnJzQwoUBMp2JNF74qQ2x9XJSOCWBezRJosGWI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=WhluC8MTcrpRscv8gged+7zO2Rg9TnVnAx+EKYOvnIwvst97Z3S3dJ5yQ9AYOVgHA g03qgZB4pYRQMHQjCuWox3tm/xc+6dqf4/7NxiHCYPzseFP9wn1PqiTEBYusxt3ljx jYhwvHLdNQXbPo4eCXjHbOPMVW2sDqed4oYno6hc= Date: Tue, 8 Sep 2020 11:55:27 +0900 From: Masami Hiramatsu To: fche@redhat.com (Frank Ch. Eigler) Cc: peterz@infradead.org, Ingo Molnar , linux-kernel@vger.kernel.org, Eddy_Wu@trendmicro.com, x86@kernel.org, davem@davemloft.net, rostedt@goodmis.org, naveen.n.rao@linux.ibm.com, anil.s.keshavamurthy@intel.com, linux-arch@vger.kernel.org, cameron@moodycamel.com, oleg@redhat.com, will@kernel.org, paulmck@kernel.org, systemtap@sourceware.org Subject: Re: [PATCH v5 00/21] kprobes: Unify kretprobe trampoline handlers and make kretprobe lockless Message-Id: <20200908115527.cf8d2b106bf1a9c4416bbc89@kernel.org> In-Reply-To: <87eendo51o.fsf@redhat.com> References: <159870598914.1229682.15230803449082078353.stgit@devnote2> <20200901190808.GK29142@worktop.programming.kicks-ass.net> <20200902093739.8bd13603380951eaddbcd8a5@kernel.org> <20200902070226.GG2674@hirez.programming.kicks-ass.net> <20200902171755.b126672093a3c5d1b3a62a4f@kernel.org> <20200902093613.GY1362448@hirez.programming.kicks-ass.net> <20200902221926.f5cae5b4ad00b8d8f9ad99c7@kernel.org> <20200902134252.GH1362448@hirez.programming.kicks-ass.net> <20200903103954.68f0c97da57b3679169ce3a7@kernel.org> <20200903110226.8963179e6a7c978e2d56c595@kernel.org> <87eendo51o.fsf@redhat.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org On Mon, 07 Sep 2020 13:44:19 -0400 fche@redhat.com (Frank Ch. Eigler) wrote: > Masami Hiramatsu writes: > > > Sorry, for noticing this point, I Cc'd to systemtap. Is systemtap taking > > care of spinlock too? > > On PRREMPT_RT configurations, systemtap uses the raw_spinlock_t > types/functions, to keep its probe handlers as atomic as we can make them. OK, if the lock is only used in the probe handlers, there should be no problem. Even if a probe hits in the NMI which happens in another kprobe handler, the probe does not call its handler (because we don't support nested kprobes* yet). But maybe you'll get warnings if you enable the lockdep. * https://lkml.kernel.org/r/158894789510.14896.13461271606820304664.stgit@devnote2 It seems that we need more work for the nested kprobes. Thank you, -- Masami Hiramatsu