From nobody Thu Sep 18 05:38:46 2025 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 19B5DC10F1B for ; Sat, 10 Dec 2022 14:07:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229934AbiLJOHo (ORCPT ); Sat, 10 Dec 2022 09:07:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43160 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230048AbiLJOGx (ORCPT ); Sat, 10 Dec 2022 09:06:53 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 917791BE98; Sat, 10 Dec 2022 06:03:56 -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 38701B82A56; Sat, 10 Dec 2022 14:03:55 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DAC70C433D2; Sat, 10 Dec 2022 14:03:53 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.96) (envelope-from ) id 1p40SG-000l40-39; Sat, 10 Dec 2022 09:03:52 -0500 Message-ID: <20221210140352.840122725@goodmis.org> User-Agent: quilt/0.66 Date: Sat, 10 Dec 2022 09:03:21 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Andrew Morton , stable@vger.kernel.org, Rafael Mendonca Subject: [for-next][PATCH 1/3] tracing: Fix race where eprobes can be called before the event References: <20221210140320.609495935@goodmis.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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-r= afaelmendsr@gmail.com/ Link: https://lore.kernel.org/all/20221117214249.2addbe10@gandalf.local.hom= e/ Cc: stable@vger.kernel.org Fixes: 7491e2c442781 ("tracing: Add a probe that attaches to trace events") Reported-by: Rafael Mendonca Signed-off-by: Steven Rostedt (Google) Acked-by: Masami Hiramatsu (Google) Signed-off-by: Masami Hiramatsu (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 123d2c0a6b68..352b65e2b910 100644 --- a/kernel/trace/trace_eprobe.c +++ b/kernel/trace/trace_eprobe.c @@ -564,6 +564,9 @@ static void eprobe_trigger_func(struct event_trigger_da= ta *data, { struct eprobe_data *edata =3D data->private_data; =20 + if (unlikely(!rec)) + return; + __eprobe_trace_func(edata, rec); } =20 --=20 2.35.1