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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_HIGH 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 13413C28CC0 for ; Thu, 30 May 2019 09:29:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D33F3254EA for ; Thu, 30 May 2019 09:29:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559208568; bh=z37S3eU6mARunEgZS89SCwtxniogx+stPp5qD9PNZqE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=FeMhPFT6Xx2uPW/0Eigyhafhsc9CjgRVxcIauRtILh/YhIGSV42KOr3vzFCxhj+nS Thx3wVIseNTDD4KY36bvXQEtKwhBOHPKvVhIICrqqC2R0KTwAWsHqKPMy8DlxL/tSA u75cJ2Qsqr/e9r5jMIS7v1W6AIlVsjR73sN8JADU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727388AbfE3J31 (ORCPT ); Thu, 30 May 2019 05:29:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:47450 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726382AbfE3J31 (ORCPT ); Thu, 30 May 2019 05:29:27 -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 B0A1E254E4; Thu, 30 May 2019 09:29:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559208566; bh=z37S3eU6mARunEgZS89SCwtxniogx+stPp5qD9PNZqE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=eEBOUttdGJAUhwxn0K17880pmCNDabd+w+xw+79EmPq4gdBBKgT3VQugK1GbcpMuo /6hIMVmb/b3MoQU+dSKbdGMMAhawH/bdR39kE9SLeqwrDU+mvUZEGmHbYADwcO/nTE RirDcdU/Czk/hkW5300xiOrNglDDkJe0Y0K3bisQ= Date: Thu, 30 May 2019 18:29:20 +0900 From: Masami Hiramatsu To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Andrew Morton , Thomas Gleixner , Peter Zijlstra , Josh Poimboeuf , Frederic Weisbecker , Joel Fernandes , Andy Lutomirski , Mark Rutland , Namhyung Kim , "Frank Ch. Eigler" Subject: Re: [RFC][PATCH 00/14 v2] function_graph: Rewrite to allow multiple users Message-Id: <20190530182920.d8ef9f3c09ba0ae1beaa605a@kernel.org> In-Reply-To: <20190529052521.6623ae7b@oasis.local.home> References: <20190520142001.270067280@goodmis.org> <20190522231955.72899b0d606adb919e8716ff@kernel.org> <20190522104027.1b2aabd8@gandalf.local.home> <20190529154740.016517ff9225680f64961097@kernel.org> <20190529052521.6623ae7b@oasis.local.home> X-Mailer: Sylpheed 3.5.1 (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-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 29 May 2019 05:25:21 -0400 Steven Rostedt wrote: > On Wed, 29 May 2019 15:47:40 +0900 > Masami Hiramatsu wrote: > > > > Hi Steve, > > > > I found that these interfaces seem tightly coupled with fgraph_ops. But that > > cause a problem when I'm using it from kretprobe. > > I was thinking that the kretprobes could use the fgraph_ops like > kprobes uses ftrace_ops. > > > > > kretprobe has 2 handlers, entry handler and return handler, and both need > > pt_regs. But fgraph_ops's entryfunc and retfunc do not pass the pt_regs. > > That is the biggest issue for me on these APIs. > > Can we expand fgraph_ops with regs parameter? > > Ug. Yeah, of course you need that :-/ > > OK, so this series isn't enough to allow kretprobes to use it yet. OK, > I plan on still keeping it because it does allow for placing function > graph tracer into instances with their own filters. OK, that will be a "regs" extension. > > I'll look into adding a REGS flag like we do with ftrace_ops. > > Does the return need all regs? Or is just the return code good enough? Since it depends on arch, I think all regs we need. And for the entry handler, we need all. Thank you, -- Masami Hiramatsu