From patchwork Sat Oct 12 00:57:49 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Rostedt X-Patchwork-Id: 11186513 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B28DB76 for ; Sat, 12 Oct 2019 00:59:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9A77221D82 for ; Sat, 12 Oct 2019 00:59:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727594AbfJLA7W (ORCPT ); Fri, 11 Oct 2019 20:59:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:57070 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726903AbfJLA7W (ORCPT ); Fri, 11 Oct 2019 20:59:22 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (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 B462421835; Sat, 12 Oct 2019 00:59:21 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.92.2) (envelope-from ) id 1iJ5ke-0004Dy-T1; Fri, 11 Oct 2019 20:59:20 -0400 Message-Id: <20191012005920.780394471@goodmis.org> User-Agent: quilt/0.65 Date: Fri, 11 Oct 2019 20:57:49 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Linus Torvalds , Ingo Molnar , Andrew Morton , Matthew Garrett , James Morris James Morris , LSM List , Linux API , Ben Hutchings , Al Viro , stable@vger.kernel.org Subject: [PATCH 2/7 v2] ftrace: Get a reference counter for the trace_array on filter files References: <20191012005747.210722465@goodmis.org> MIME-Version: 1.0 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: From: "Steven Rostedt (VMware)" The ftrace set_ftrace_filter and set_ftrace_notrace files are specific for an instance now. They need to take a reference to the instance otherwise there could be a race between accessing the files and deleting the instance. It wasn't until the :mod: caching where these file operations stated referencing the trace_arry directly. Cc: stable@vger.kernel.org Fixes: 673feb9d76ab3 ("ftrace: Add :mod: caching infrastructure to trace_array") Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ftrace.c | 27 ++++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 62a50bf399d6..32c2eb167de0 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3540,21 +3540,22 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag, struct ftrace_hash *hash; struct list_head *mod_head; struct trace_array *tr = ops->private; - int ret = 0; + int ret = -ENOMEM; ftrace_ops_init(ops); if (unlikely(ftrace_disabled)) return -ENODEV; + if (tr && trace_array_get(tr) < 0) + return -ENODEV; + iter = kzalloc(sizeof(*iter), GFP_KERNEL); if (!iter) - return -ENOMEM; + goto out; - if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) { - kfree(iter); - return -ENOMEM; - } + if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) + goto out; iter->ops = ops; iter->flags = flag; @@ -3584,13 +3585,13 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag, if (!iter->hash) { trace_parser_put(&iter->parser); - kfree(iter); - ret = -ENOMEM; goto out_unlock; } } else iter->hash = hash; + ret = 0; + if (file->f_mode & FMODE_READ) { iter->pg = ftrace_pages_start; @@ -3602,7 +3603,6 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag, /* Failed */ free_ftrace_hash(iter->hash); trace_parser_put(&iter->parser); - kfree(iter); } } else file->private_data = iter; @@ -3610,6 +3610,13 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag, out_unlock: mutex_unlock(&ops->func_hash->regex_lock); + out: + if (ret) { + kfree(iter); + if (tr) + trace_array_put(tr); + } + return ret; } @@ -5037,6 +5044,8 @@ int ftrace_regex_release(struct inode *inode, struct file *file) mutex_unlock(&iter->ops->func_hash->regex_lock); free_ftrace_hash(iter->hash); + if (iter->tr) + trace_array_put(iter->tr); kfree(iter); return 0;