From patchwork Wed Nov 23 21:43:23 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 25219 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:adf:f944:0:0:0:0:0 with SMTP id q4csp3043393wrr; Wed, 23 Nov 2022 13:46:58 -0800 (PST) X-Google-Smtp-Source: AA0mqf47jUdnQr/Rrloz3RCyvFW4uaB983LQMIihjB9HPepu/KZ0oKeN2LYFVUQ+Dmaz5yFu2CoA X-Received: by 2002:a17:90a:6c26:b0:218:f02a:f08f with SMTP id x35-20020a17090a6c2600b00218f02af08fmr3337642pjj.1.1669240018465; Wed, 23 Nov 2022 13:46:58 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1669240018; cv=none; d=google.com; s=arc-20160816; b=nA+TvDWXHlAhGXtGxLhC+VekhkU6N1wpxSofX1UYGgLgGe2dz393J/8WJrX59Ilj3v eIkExv9/J8GuGgKUa6scIieD2DeBSbwj61Mi58rOsF1TH8jsAs3IvrNYSnWprKM0NDCL rlH+poHmEbHa3lDZK3CywSSz5Dn0byEFiuqUmVYmk/j23b0rNEwEQrf+hkfEUTPIDF1m 9mqnBc1g6M9KMuxqgstIunb41xiuBcEssBQ/Z5UU2AhKs93ZyecJI/eu5GtaMRERhENT TiNHOguSpdTLobUpJmD1BPXvEk/DNkjpyvEFYG1gJ4LOqeCURsnwZ2f1Vafc2cGmQLFj 68dg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :message-id:subject:cc:to:from:date; bh=qaWLO/lNBYnqMfnGii9QLe1oa0K+A1KpDlPivj8Ltas=; b=OTt2WKEPcnx5bh0/QVzJmluXd9lfhacfNBvG1mF61PCkg7wOzq0G33Afzf/Wb3R+An 8JjXjGuwcdHhcFXGbQVIOgiZBOU8c0bNn6L16v8QpF4ADkcoV+QUkuQ3k7R0pv8eZ3h2 LWs39xyA9hsHJHkKvhk9L+2WnR5QB5otrdXaC6gWbcb8AhEBHJw4SamYkz+gj+nWwXCx +aXljnq53qZCnL/ncdX66poi0q1wrEYZp+mkSJ6NPJlaw695ayNaQhz46JbzxMgx9K7t aONM6Pgo2Q0hfg8W41MAKWLT/r3YloveNx0oYIVRmYfDE6w9bVwil7+F2L7tYgqB81PA DodQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id v10-20020a63f20a000000b0047701a2244esi16368982pgh.773.2022.11.23.13.46.45; Wed, 23 Nov 2022 13:46:58 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234982AbiKWVn3 (ORCPT + 99 others); Wed, 23 Nov 2022 16:43:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55360 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230009AbiKWVn2 (ORCPT ); Wed, 23 Nov 2022 16:43:28 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8B18DC689C; Wed, 23 Nov 2022 13:43:26 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 2972861F36; Wed, 23 Nov 2022 21:43:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EF86BC433D6; Wed, 23 Nov 2022 21:43:24 +0000 (UTC) Date: Wed, 23 Nov 2022 16:43:23 -0500 From: Steven Rostedt To: LKML , Linux Trace Kernel Cc: Masami Hiramatsu , Tom Zanussi Subject: [PATCH] tracing: Fix race where histograms can be called before the event Message-ID: <20221123164323.03450c3a@gandalf.local.home> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-Spam-Status: No, score=-6.7 required=5.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1750325021767263664?= X-GMAIL-MSGID: =?utf-8?q?1750325021767263664?= From: "Steven Rostedt (Google)" commit 94eedf3dded5 ("tracing: Fix race where eprobes can be called before the event") fixed an issue where if an event is soft disabled, and the trigger is being added, there's a small window where the event sees that there's a trigger but does not see that it requires reading the event yet, and then calls the trigger with the record == NULL. This could be solved with adding memory barriers in the hot path, or to make sure that all the triggers requiring a record check for NULL. The latter was chosen. Commit 94eedf3dded5 set the eprobe trigger handle to check for NULL, but the same needs to be done with histograms. Link: https://lore.kernel.org/linux-trace-kernel/20221118211809.701d40c0f8a757b0df3c025a@kernel.org/ Cc: stable@vger.kernel.org Fixes: 7491e2c442781 ("tracing: Add a probe that attaches to trace events") Reported-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google) Acked-by: Masami Hiramatsu (Google) --- kernel/trace/trace_events_hist.c | 3 +++ 1 file changed, 3 insertions(+) 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) {