From patchwork Sun Nov 20 20:07:13 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 23453 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:adf:f944:0:0:0:0:0 with SMTP id q4csp1250567wrr; Sun, 20 Nov 2022 12:09:08 -0800 (PST) X-Google-Smtp-Source: AA0mqf6M7QowdnySHiCtNmCxZU2SQSSNzY3jnB2sb3iW4vbwtLJUgA9okd0ZS9WnMLavew5ZMrrH X-Received: by 2002:a63:5819:0:b0:476:8ce9:be5d with SMTP id m25-20020a635819000000b004768ce9be5dmr991253pgb.15.1668974948610; Sun, 20 Nov 2022 12:09:08 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1668974948; cv=none; d=google.com; s=arc-20160816; b=XXJBaD53cHi2qGM75STivMmxlOFvn4RFjOZUzFRy+Qp3y5eO1zOiujxRFeR3KkGiKs 9KkUO8InMRDzhZ/OgtDsmf1PPpqomAEdtU4RlUy+ar3vbKAHZ8wmRJONg2whJhq0vS9n Gfq9WQaDCjkypdFKgQ60YJPumRSDKPmFOUdFIlbIBMLyyBUo12ol1D3piHWg9Hz2W4s0 LaY9FYd+NkgQbh0GdEttaCqFXJqNoXj7aiYzygPMaC4TgXqXgZVvjJtnPB9It25l0wb9 +n6Q1fbO65oFFb2y2M4ktOQ1ePsDMDnNJyHpkOjZx/2J+cgkizN7qz7pWxNYUm1PUVk2 1C/Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:mime-version:references:subject:cc:to:from:date :user-agent:message-id; bh=gnsaVg8zADQYWA66IgT8pEmFGwqQ2P1VI0grs8O/Imw=; b=oAzWUcy4DEr2R3RrUYGpA3YAUAGDLxHfxyS4mmOaD/08gHkkj4utTR53w4PziWrw4c CxJLUOliM6p5Xt4jD8tEt7ErGC/s1+gm1MHs/hMPbXJw7sz88vfJhR5Gl6zyr0Uh3shZ 3YooojnHV4k3ytt5cs29QFOUP1GUPZKSclsuvF1k4A3YfPUG9Kv/YmFry8D8EmRMg3OX H4pj3ONbPoTCl3s5zOjG8vPw8K+8q3RI+U8zp3M0bbAZmc39VElr26WdfurR46g5xx3B hyANslRzPk1dgCF56MX9u09SU5PPlQ1srvqvVbzvQ4mauilV0PhL2RyUDdej1ayOu8Tu L5ow== 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 e18-20020a170903241200b00188f0ca258asi9283872plo.388.2022.11.20.12.08.55; Sun, 20 Nov 2022 12:09:08 -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 S229904AbiKTUIM (ORCPT + 99 others); Sun, 20 Nov 2022 15:08:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52668 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229751AbiKTUHl (ORCPT ); Sun, 20 Nov 2022 15:07:41 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B6B391E729; Sun, 20 Nov 2022 12:07:38 -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 EDB4260D39; Sun, 20 Nov 2022 20:07:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C6FD6C433D7; Sun, 20 Nov 2022 20:07:36 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.96) (envelope-from ) id 1owqbH-00Di9j-2x; Sun, 20 Nov 2022 15:07:35 -0500 Message-ID: <20221120200735.791518959@goodmis.org> User-Agent: quilt/0.66 Date: Sun, 20 Nov 2022 15:07:13 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Andrew Morton , Linux Trace Kernel , Tzvetomir Stoyanov , Tom Zanussi , stable@vger.kernel.org, Rafael Mendonca Subject: [for-linus][PATCH 13/13] tracing: Fix race where eprobes can be called before the event References: <20221120200700.725968899@goodmis.org> 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?1750047075907979180?= X-GMAIL-MSGID: =?utf-8?q?1750047075907979180?= From: "Steven Rostedt (Google)" The flag that tells the event to call its triggers after reading the event is set for eprobes after the eprobe is enabled. This leads to a race where the eprobe may be triggered at the beginning of the event where the record information is NULL. The eprobe then dereferences the NULL record causing a NULL kernel pointer bug. Test for a NULL record to keep this from happening. Link: https://lore.kernel.org/linux-trace-kernel/20221116192552.1066630-1-rafaelmendsr@gmail.com/ Link: https://lore.kernel.org/linux-trace-kernel/20221117214249.2addbe10@gandalf.local.home Cc: Linux Trace Kernel Cc: Tzvetomir Stoyanov Cc: Tom Zanussi Cc: stable@vger.kernel.org Fixes: 7491e2c442781 ("tracing: Add a probe that attaches to trace events") Acked-by: Masami Hiramatsu (Google) Reported-by: Rafael Mendonca Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace_eprobe.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c index 5dd0617e5df6..9cda9a38422c 100644 --- a/kernel/trace/trace_eprobe.c +++ b/kernel/trace/trace_eprobe.c @@ -563,6 +563,9 @@ static void eprobe_trigger_func(struct event_trigger_data *data, { struct eprobe_data *edata = data->private_data; + if (unlikely(!rec)) + return; + __eprobe_trace_func(edata, rec); }