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 F2E73C77B7A for ; Mon, 12 Jun 2023 02:58:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233932AbjFLC6A (ORCPT ); Sun, 11 Jun 2023 22:58:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41034 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229476AbjFLC57 (ORCPT ); Sun, 11 Jun 2023 22:57:59 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B32C2E42; Sun, 11 Jun 2023 19:57:58 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 4FA4261BBA; Mon, 12 Jun 2023 02:57:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 84A66C433EF; Mon, 12 Jun 2023 02:57:56 +0000 (UTC) Date: Sun, 11 Jun 2023 22:57:54 -0400 From: Steven Rostedt To: Yonghong Song Cc: Jiri Olsa , Masami Hiramatsu , Mark Rutland , Andrii Nakryiko , lkml , linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org, Andrii Nakryiko , Jackie Liu Subject: Re: [PATCHv2] ftrace: Show all functions with addresses in available_filter_functions_addrs Message-ID: <20230611225754.01350a50@gandalf.local.home> In-Reply-To: <20230611225407.3e9b8ad2@gandalf.local.home> References: <20230611130029.1202298-1-jolsa@kernel.org> <53a11f31-256d-e7bc-eca5-597571076dc5@meta.com> <20230611225407.3e9b8ad2@gandalf.local.home> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; 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-trace-kernel@vger.kernel.org On Sun, 11 Jun 2023 22:54:07 -0400 Steven Rostedt wrote: > > Also, if there are multiple same static functions with > > different addresses, user space might need to check dwarf or > > proposed BTF_KIND_KFUNC (which encode kallsyms addresses) > > to find whether entry in available_filter_functions_addrs > > to be used. But addresses may not match. How this issue could > > be resolved? > > Easy, you use the address between two other addresses in kallsyms. The > address is still in the function. The addresses in kallsyms is the starting > address, but there's cases that the patch location is not at the start. Not to mention, you can still use the kallsyms address. If you did the work to find it, then use it (it may not be as efficient as I mentioned before). That's basically what is done today (so I am told), and this patch was to create a file where you don't need to look up kallsyms when you know which function to use. The functions are sorted by address, so if you know of a unique function near the duplicate, you just find the duplicate that's near the unique function name. -- Steve