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 X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CD359ECDE4B for ; Thu, 8 Nov 2018 14:41:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8F3792081D for ; Thu, 8 Nov 2018 14:41:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="T3rg8McE" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8F3792081D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727078AbeKIARp (ORCPT ); Thu, 8 Nov 2018 19:17:45 -0500 Received: from mail.kernel.org ([198.145.29.99]:35828 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726509AbeKIARo (ORCPT ); Thu, 8 Nov 2018 19:17:44 -0500 Received: from tzanussi-mobl.hsd1.il.comcast.net (c-98-220-238-81.hsd1.il.comcast.net [98.220.238.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CCB282086C; Thu, 8 Nov 2018 14:41:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1541688116; bh=ZWLW47bXHn7F3r6H7XG7E2djdbp2iZLEvoiD+fZi5B4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:In-Reply-To: References:From; b=T3rg8McEl7tozyTnP4fyfppFEazo0LoC5CeCem1yANzVrPvK/7zIem4lGOwmT2c25 us9p7Vaxz1o2qm1dDNFLHAMLYcv79qt2SqWEZ2BU42dfc8LAOBnNiaccv3iGz2Ar99 HZiV7Yzc8U5c6dKsIG2Pp8aN3nzuhkS+QJIhAlxE= From: Tom Zanussi To: rostedt@goodmis.org Cc: vincent@bernat.ch, linux-kernel@vger.kernel.org Subject: [PATCH 1/2] tracing: Prevent hist_field_var_ref() from accessing NULL tracing_map_elts Date: Thu, 8 Nov 2018 08:41:48 -0600 Message-Id: X-Mailer: git-send-email 2.14.1 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tom Zanussi hist_field_var_ref() is an implementation of hist_field_fn_t(), which can be called with a null tracing_map_elt elt param when assembling a key in event_hist_trigger(). In the case of hist_field_var_ref() this doesn't make sense, because a variable can only be resolved by looking it up using an already assembled key i.e. a variable can't be used to assemble a key since the key is required in order to access the variable. Upper layers should prevent the user from constructing a key using a variable in the first place, but in case one slips through, it shouldn't cause a NULL pointer dereference. Also if one does slip through, we want to know about it, so emit a one-time warning in that case. Signed-off-by: Tom Zanussi Reported-by: Vincent Bernat --- 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 eb908ef2ecec..3795207a48a0 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -1632,6 +1632,9 @@ static u64 hist_field_var_ref(struct hist_field *hist_field, struct hist_elt_data *elt_data; u64 var_val = 0; + if (WARN_ON_ONCE(!elt)) + return var_val; + elt_data = elt->private_data; var_val = elt_data->var_ref_vals[hist_field->var_ref_idx]; -- 2.14.1