From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 65E731C31 for ; Wed, 23 Nov 2022 09:53:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CBCC0C433C1; Wed, 23 Nov 2022 09:53:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1669197182; bh=r/KD+Loc1bRhvWnz5vxl9PaccKxnBDk2Ng7IRLJ8Wv0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DJwGAYMyEPVEhvPX6uALTtwJYkPWKOOkVB8ZSlYc9JgZAQFfenWLK21hdQf9a1swl YVN8e8Sv7efNq2Imb6S3Hpwx4c8QVc8211cwGFyP8bEEWqxUKCEfSUrq2gd2QwFFy0 +BQ+WGqnxmfHpD0Piakp75S4bhjao16CsqMkxJFg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Linux Trace Kernel , Tzvetomir Stoyanov , Tom Zanussi , "Masami Hiramatsu (Google)" , Rafael Mendonca , "Steven Rostedt (Google)" Subject: [PATCH 6.0 204/314] tracing: Fix race where eprobes can be called before the event Date: Wed, 23 Nov 2022 09:50:49 +0100 Message-Id: <20221123084634.797557114@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221123084625.457073469@linuxfoundation.org> References: <20221123084625.457073469@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Steven Rostedt (Google) commit 94eedf3dded5fb472ce97bfaf3ac1c6c29c35d26 upstream. 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) Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace_eprobe.c | 3 +++ 1 file changed, 3 insertions(+) --- a/kernel/trace/trace_eprobe.c +++ b/kernel/trace/trace_eprobe.c @@ -560,6 +560,9 @@ static void eprobe_trigger_func(struct e { struct eprobe_data *edata = data->private_data; + if (unlikely(!rec)) + return; + __eprobe_trace_func(edata, rec); }