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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, T_DKIMWL_WL_HIGH,UNPARSEABLE_RELAY,URIBL_BLOCKED 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 9E489C1B0F2 for ; Wed, 20 Jun 2018 11:08:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4B37120836 for ; Wed, 20 Jun 2018 11:08:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="XO/cyHSq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4B37120836 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com 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 S1753938AbeFTLIZ (ORCPT ); Wed, 20 Jun 2018 07:08:25 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:48510 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752914AbeFTLIY (ORCPT ); Wed, 20 Jun 2018 07:08:24 -0400 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w5KB4JnY012376; Wed, 20 Jun 2018 11:08:10 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : mime-version : content-type; s=corp-2017-10-26; bh=f8bFcp/3AuGfmcFnpVWlD+mZstpvuTSqyUThfG1T//I=; b=XO/cyHSqdLK4PPKQDF7IkezuHP8llUig40iq775B69XbqNp93ypJAbJgva1tTPUUycvE Drv4cP81oQTtXpHYiQ+50G85zxoFjFIaddX0+fHnxhYliyH6GPzR2pv8UAVzpwNuQdLM zOra/rzOQklhc8HhtuUxqT5zzD04II3Q/UHw/5PRKdxEayEg1siR+jgx6co1ZcKoyefS EuWtb9k93a9MxWBWDghJf5GZzTE1ahA8iUKcfryPc8q9p2metq3E76pQAcOnqzsuq2x3 0RGltaDnXG8kkiGcKt2c7GLjJfeyupynTQNKiFczyVX+wblsgLOlBT9aESw8Df+lYfYg Ow== Received: from userv0021.oracle.com (userv0021.oracle.com [156.151.31.71]) by aserp2120.oracle.com with ESMTP id 2jmtgwuyv0-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 20 Jun 2018 11:08:10 +0000 Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userv0021.oracle.com (8.14.4/8.14.4) with ESMTP id w5KB89bj012765 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 20 Jun 2018 11:08:09 GMT Received: from abhmp0010.oracle.com (abhmp0010.oracle.com [141.146.116.16]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id w5KB88Ae004569; Wed, 20 Jun 2018 11:08:08 GMT Received: from kili.mountain (/197.157.34.185) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 20 Jun 2018 04:08:08 -0700 Date: Wed, 20 Jun 2018 14:08:00 +0300 From: Dan Carpenter To: Steven Rostedt Cc: Ingo Molnar , linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: [PATCH] tracing: Fix an off by one in __next() Message-ID: <20180620110758.crunhd5bfep7zuiz@kili.mountain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Mailer: git-send-email haha only kidding User-Agent: NeoMutt/20170113 (1.7.2) X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8929 signatures=668702 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1805220000 definitions=main-1806200127 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The > should be >= to prevent an off by one bug. >From reviewing the code, it seems possible for stack_trace_max.nr_entries to be set to .max_entries and in that case we would be reading one element beyond the end of the stack_dump_trace[] array. If it's not set to .max_entries then the bug doesn't affect runtime. Signed-off-by: Dan Carpenter diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index 4237eba4ef20..6e3edd745c68 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -286,7 +286,7 @@ __next(struct seq_file *m, loff_t *pos) { long n = *pos - 1; - if (n > stack_trace_max.nr_entries || stack_dump_trace[n] == ULONG_MAX) + if (n >= stack_trace_max.nr_entries || stack_dump_trace[n] == ULONG_MAX) return NULL; m->private = (void *)n;