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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_2 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 2867CC433E7 for ; Wed, 14 Oct 2020 15:35:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CECC02222A for ; Wed, 14 Oct 2020 15:35:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730321AbgJNPfU (ORCPT ); Wed, 14 Oct 2020 11:35:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:44370 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729318AbgJNPfU (ORCPT ); Wed, 14 Oct 2020 11:35:20 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (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 A938C2222A; Wed, 14 Oct 2020 15:35:19 +0000 (UTC) Date: Wed, 14 Oct 2020 11:35:17 -0400 From: Steven Rostedt To: Masami Hiramatsu Cc: LKML , Ingo Molnar Subject: Re: [RFC PATCH 1/1] tracepoints: tree-wide: Replace %p with %px Message-ID: <20201014113517.512fbd07@gandalf.local.home> In-Reply-To: <20201015001104.593651d4e07bc3d4597e0771@kernel.org> References: <160266594977.74973.9883936722540767319.stgit@devnote2> <160266595921.74973.16021029265750003477.stgit@devnote2> <20201014093813.74490c26@gandalf.local.home> <20201015001104.593651d4e07bc3d4597e0771@kernel.org> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 15 Oct 2020 00:11:04 +0900 Masami Hiramatsu wrote: > On Wed, 14 Oct 2020 09:38:13 -0400 > Steven Rostedt wrote: > > > Hmm, would you mean we always run such conversion on printing the trace > buffer for each entry? It could be much overhead because we need allocate > memory (%p->%px increase 1 byte) and format conversion (with copying it). I was thinking of having a single buffer allocated to the iterator (could increase in size when needed). Really, the output isn't that time critical, and running a conversion on all events each time shouldn't be that bad. And if it is, we could have a cache in the iter for a set of events to handle. Note, the conversion only needs to happen for events that have a %p in the fmt, and only those need to be cached. Then those buffers could be freed when the iter is freed. > Maybe we can avoid repeating it using a kind of cache, but it also consumes > memory. And as I pointed, the security reason is meaningless because there > are raw addresses in raw data which user can read... > Could you tell me what is your point? Making the code change as small as > possible? > It's about not having to worry about this in the future. Otherwise, we'll be playing whack-a-mole on making all %px in new trace events. -- Steve