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 9C6C9C433FE for ; Wed, 23 Nov 2022 21:03:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229728AbiKWVC6 (ORCPT ); Wed, 23 Nov 2022 16:02:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54944 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236590AbiKWVCw (ORCPT ); Wed, 23 Nov 2022 16:02:52 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0FDF22A96D; Wed, 23 Nov 2022 13:02:51 -0800 (PST) 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 ams.source.kernel.org (Postfix) with ESMTPS id CA188B82488; Wed, 23 Nov 2022 21:02:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C7C96C433C1; Wed, 23 Nov 2022 21:02:47 +0000 (UTC) Date: Wed, 23 Nov 2022 16:02:46 -0500 From: Steven Rostedt To: "Masami Hiramatsu (Google)" Cc: LKML , Linux Trace Kernel , Rafael Mendonca , Tzvetomir Stoyanov , Tom Zanussi Subject: Re: [PATCH] tracing: Fix race where eprobes can be called before the event Message-ID: <20221123160246.348c11b4@gandalf.local.home> In-Reply-To: <20221118211809.701d40c0f8a757b0df3c025a@kernel.org> References: <20221117214249.2addbe10@gandalf.local.home> <20221118211809.701d40c0f8a757b0df3c025a@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 Fri, 18 Nov 2022 21:18:09 +0900 Masami Hiramatsu (Google) wrote: > This looks good to me. > > Acked-by: Masami Hiramatsu (Google) > > BTW, would other trigger callbacks also need to add similar checks? I just checked, and yes, I think that histograms (the only other trigger that has EVENT_CMD_FL_NEEDS_REC set) has the same issue, and requires: diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 087c19548049..1c82478e8dff 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -5143,6 +5143,9 @@ static void event_hist_trigger(struct event_trigger_data *data, void *key = NULL; unsigned int i; + if (unlikely(!rbe)) + return; + memset(compound_key, 0, hist_data->key_size); for_each_hist_key_field(i, hist_data) { I'll add that next. -- Steve