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=-9.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,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 A2884C10F0E for ; Thu, 18 Apr 2019 15:19:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7415F217D7 for ; Thu, 18 Apr 2019 15:19:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1555600762; bh=2OBE/cFCwpdJYJzETJ/GvlSo2GHShxpC+P75/bfURJU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:In-Reply-To: References:List-ID:From; b=Jh6MIg4gbNVxYVwkZ1rTy0JOGDGSyhETOf03slEDnn8nvygrlAq9gRSe/cKwcHzZ0 vKw9QUpbw0wuXa73PD6NCneZ1MgUpRewH7aDkQtYIxN+WzKKdblm/JFgYBn/TWabQ4 t3GI27pkt487Z4TLfJ/MX0y15RSE8JIUrOSqCX8E= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389570AbfDRPTV (ORCPT ); Thu, 18 Apr 2019 11:19:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:52958 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388548AbfDRPTS (ORCPT ); Thu, 18 Apr 2019 11:19:18 -0400 Received: from localhost.localdomain (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 31BD320674; Thu, 18 Apr 2019 15:19:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1555600757; bh=2OBE/cFCwpdJYJzETJ/GvlSo2GHShxpC+P75/bfURJU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:In-Reply-To: References:From; b=VP8NJ9L4XOQw0FDkk1X3lmTWYsvXAwZY9LT4D86hx8l+pFLCcPCU2Ldl08yg32urr OZbxnhL4P540xM0+12mxPnFIz8wpiPsHaTNM3W1RnR688o41wDVAdCTTocNKmxSZY1 b4BxtTsY0jvj3xTHr6yQLWo5/EzsHQ6lcNooOtz0= From: Tom Zanussi To: rostedt@goodmis.org Cc: vincent@bernat.ch, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org Subject: [PATCH v2 1/3] tracing: Prevent hist_field_var_ref() from accessing NULL tracing_map_elts Date: Thu, 18 Apr 2019 10:18:50 -0500 Message-Id: <64ec8dc15c14d305295b64cdfcc6b2b9dd14753f.1555597045.git.tom.zanussi@linux.intel.com> 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 a1136e043f17..453f51ef83ca 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -1854,6 +1854,9 @@ 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