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=-8.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 3AF69C31E5E for ; Mon, 17 Jun 2019 21:33:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 04F0B2133F for ; Mon, 17 Jun 2019 21:33:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560807205; bh=zI8Hg35TXwTztuYQyEiWjGDdTu0c1cknvU8BVyrffpM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Yl0At6Dy2QtAYvXRD27yoZQWb4caSGQqVDiFkOvoRTuxxleS62h+s+mriCp0EAeOg 2klFR6OmDc+cE4M2FT+9Dwe1kocbM/1zdTKVEc0iOKr/b4cwJAsV2dzaFa/T7xAdfL 3s1uCIRxGxDs6JRvfdi8gbihwHTD0XjkkzuYSIgo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729626AbfFQV0L (ORCPT ); Mon, 17 Jun 2019 17:26:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:52578 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729837AbfFQV0I (ORCPT ); Mon, 17 Jun 2019 17:26:08 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C1D9D2070B; Mon, 17 Jun 2019 21:26:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560806767; bh=zI8Hg35TXwTztuYQyEiWjGDdTu0c1cknvU8BVyrffpM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=csx/NrO6A3UfFFx+IbddhFU8Y5FXJj7GNvdnmV0I0mgaMfMLW349skhrXZtZQAh6o DDOV1+wfVS4Y68Xlm2xGVMVPMAZRqvUubAarp85srKsvOBnrhwo4k78agNVXI5O+k+ RUFpcPG7QEBAgG/U6ccy0nvhst2uupyrODS18dSY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vincent Bernat , Tom Zanussi , "Steven Rostedt (VMware)" , Sasha Levin Subject: [PATCH 4.19 50/75] tracing: Prevent hist_field_var_ref() from accessing NULL tracing_map_elts Date: Mon, 17 Jun 2019 23:10:01 +0200 Message-Id: <20190617210754.686952639@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190617210752.799453599@linuxfoundation.org> References: <20190617210752.799453599@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org [ Upstream commit 55267c88c003a3648567beae7c90512d3e2ab15e ] 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. Link: http://lkml.kernel.org/r/64ec8dc15c14d305295b64cdfcc6b2b9dd14753f.1555597045.git.tom.zanussi@linux.intel.com Reported-by: Vincent Bernat Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Sasha Levin --- 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 11853e90b649..3f34cfb66a85 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]; -- 2.20.1