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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A85BEC43334 for ; Tue, 14 Jun 2022 19:22:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233902AbiFNTWC (ORCPT ); Tue, 14 Jun 2022 15:22:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33970 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229988AbiFNTWB (ORCPT ); Tue, 14 Jun 2022 15:22:01 -0400 Received: from mail-ed1-x52c.google.com (mail-ed1-x52c.google.com [IPv6:2a00:1450:4864:20::52c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0E6DE29C83; Tue, 14 Jun 2022 12:21:58 -0700 (PDT) Received: by mail-ed1-x52c.google.com with SMTP id d14so12990836eda.12; Tue, 14 Jun 2022 12:21:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:date:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=LQS7VowSx/S+w+iLmTbGWcWoA0CZ0lVjX4LifZSTEZE=; b=mkwtIuPkjTinjeBHAd5Uk6q8Vvx8bh0z0iEkAXqqNBw0Y2+CaMFvPqlvGLfXZITELb YBuK5VTzTFnmw0pmtEtLqiAnB3BAkGBcOwLfU4IBLEqjdhFAkX4fn1jcqAYCbmpbbe9y qIQB3roKngMuYrqLQt6tHVobbxTPTy9wEl872Z//dlchLBqIvw3Af4yqRLFkleyz4OAS E4Br6e17PtEpu6UWOBiNRWsMVGLCX50rE/iUnrvfXR5ZDZC3g4f6ef5AIWvMgPJwesgh GvBCNQYwantRaRYldKt9Ga3WER1QqMjDTovwiqcGbcXGxrw9I5xBrMSRqI/v8o/HAw0P YBoQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:date:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=LQS7VowSx/S+w+iLmTbGWcWoA0CZ0lVjX4LifZSTEZE=; b=eZUhVstDdf+00VBiB5nwTa45MyIDg7F+b7qRVF7dixsVu9DOgFzOaTQdeEYJJYzPD1 LYxAI7BDl7xyibURp6L9j5HasELCk/nCNIJ2s3ImWiDLLmFwCVCkwTUoxFhE59CYwAb2 /Liw79FfKhk/YQG5T3a3FgFFsuH3aGeGJZ0l4FU8mD3WMgh0tGWnhh14uFthPQDhmFfR UhFRSlV1VdOi1UXkUkJcPaoHzS29FMDHqbxF8iwAtN96syNlB1R3o+kZ/NKNomfBttkm peeEtkbQoYD9S6qbl2vk+Wwf2aufecgGsPUbXuJrUNwnzpUBBKbrxTMDZF8m/6eUdsOC 7OZg== X-Gm-Message-State: AOAM530Pq8eJpZ4v0hMhTZvtfgBSQKL3teW//5JJQQWd+HKJJND9MYSK j12r69j0DDa+Pf0T1SOmFSs= X-Google-Smtp-Source: AGRyM1uXyoNKfAQKrnzBo+Kl6QJ1CIMw3KffZh36hLSPIpfuU3sWnM3dANTOgt0/85LMRqh7ljL/yg== X-Received: by 2002:a05:6402:2548:b0:42d:dd95:5bfe with SMTP id l8-20020a056402254800b0042ddd955bfemr7928262edb.285.1655234516470; Tue, 14 Jun 2022 12:21:56 -0700 (PDT) Received: from krava ([83.240.63.226]) by smtp.gmail.com with ESMTPSA id s11-20020aa7d78b000000b0042bca34bd15sm7567589edq.95.2022.06.14.12.21.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Jun 2022 12:21:55 -0700 (PDT) From: Jiri Olsa X-Google-Original-From: Jiri Olsa Date: Tue, 14 Jun 2022 21:21:53 +0200 To: Andrii Nakryiko Cc: Steven Rostedt , Jiri Olsa , Alexei Starovoitov , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Network Development , bpf , lkml , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Masami Hiramatsu Subject: Re: [PATCHv2 bpf 3/3] bpf: Force cookies array to follow symbols sorting Message-ID: References: <20220606184731.437300-4-jolsa@kernel.org> <20220608084023.4be8ffe2@gandalf.local.home> <20220608120830.1ff5c5eb@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Jun 09, 2022 at 11:32:59AM -0700, Andrii Nakryiko wrote: > On Wed, Jun 8, 2022 at 9:08 AM Steven Rostedt wrote: > > > > On Wed, 8 Jun 2022 08:59:50 -0700 > > Andrii Nakryiko wrote: > > > > > Would it be possible to preprocess ftrace_pages to remove such invalid > > > records (so that by the time we have to report > > > available_filter_functions there are no invalid records)? Or that data > > > is read-only when kernel is running? > > > > It's possible, but will be time consuming (slow down boot up) and racy. In > > other words, I didn't feel it was worth it. > > > > We can add it. How much of an issue is it to have these place holders for > > you? Currently, I only see it causes issues with tests. Is it really an > > issue for use cases? > > I have the tool (retsnoop) that uses available_filter_functions, I'll > have to update it to ignore such entries. It's a small inconvenience, > once you know about this change, but multiply that for multiple users > that use available_filter_functions for some sort of generic tooling > doing kprobes/tracing, and it adds up. So while it's not horrible, > ideally user-visible data shouldn't have non-usable placeholders. > > How much slowdown would you expect on start up? Not clear what would > be racy about this start up preprocessing, but I believe you. > > So in summary, it's not the end of the world, but as a user I'd prefer > not to know about this quirk, of course :) ok, I'l resend with the test workaround jirka