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 D1077C25B08 for ; Sat, 20 Aug 2022 12:48:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346200AbiHTMsc (ORCPT ); Sat, 20 Aug 2022 08:48:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51352 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229605AbiHTMs2 (ORCPT ); Sat, 20 Aug 2022 08:48:28 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0C51F21E0B; Sat, 20 Aug 2022 05:48:26 -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 17EFD61226; Sat, 20 Aug 2022 12:48:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A0111C433D6; Sat, 20 Aug 2022 12:48:24 +0000 (UTC) Date: Sat, 20 Aug 2022 08:48:37 -0400 From: Steven Rostedt To: "Masami Hiramatsu (Google)" Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Andrew Morton , Tzvetomir Stoyanov , Tom Zanussi , stable@vger.kernel.org Subject: Re: [PATCH 2/4] tracing/eprobes: Do not hardcode $comm as a string Message-ID: <20220820084837.4d6a95e4@gandalf.local.home> In-Reply-To: <20220820201824.5637c4feff4a7674aebde60a@kernel.org> References: <20220820014035.531145719@goodmis.org> <20220820014833.035925907@goodmis.org> <20220820201824.5637c4feff4a7674aebde60a@kernel.org> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 20 Aug 2022 20:18:24 +0900 Masami Hiramatsu (Google) wrote: > > Do not assume that comm is a string. Not to mention, it currently forces > > comm fields to fault, as string processing for event probes is currently > > broken. > > Indeed. There should be an event argument which names "comm". > Eprobe might refer it. BTW, does eprobe use any special common fields? > I originally introduced "$" variable for such special variables. I used the '$' for denoting the fields, as it was the easiest way to integrate with trace_probe.c. There's no special variables, but this patch series now allows '@' as well as if $comm (or $COMM) is not a field, it acts the same as $comm for kprobes. Filtering and histograms do the same thing (use 'comm' as the event field, or has the current->comm if the event does not have 'comm' as a field). I should probably make "$common_comm" used too. -- Steve