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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,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 99D93FA3728 for ; Wed, 16 Oct 2019 22:02:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6EAB020872 for ; Wed, 16 Oct 2019 22:02:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571263363; bh=ISLKsaq/FqtvBASq4WxtSQF4p5xLaOZAWFmz4fOgPG8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=rBnlaGEBPxvC+1zunuf/bxcfXPsaXGOmH8IYIDvtVIaEXvTYg8ek9JUQx3LUQEc8P hCLNqT7+ogXKE52owTSac52RNIjp9/oGw8ISk3hkxmA0PpamKchcoi5VjhsqHoX4PF 5D1Zkp/ykwphSVfWymykGmqd4CchzTUykhAuczK4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2439028AbfJPWCm (ORCPT ); Wed, 16 Oct 2019 18:02:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:54638 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2438572AbfJPV7i (ORCPT ); Wed, 16 Oct 2019 17:59:38 -0400 Received: from localhost (unknown [192.55.54.58]) (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 8C63121D7E; Wed, 16 Oct 2019 21:59:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571263177; bh=ISLKsaq/FqtvBASq4WxtSQF4p5xLaOZAWFmz4fOgPG8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YWLt+QWCftWkKUxJlwf8PzDyDyMWRCsD2Kb0PsxJ896U7vYC/U4vM5F/prRparhFF b+nyY7HzMW+InWwkJOBCzp4xk2Qpb3smUgMkn2kVoLBe+o36Du9Q/jLsHVDyIuJ3Wj 5gX8gHfxnPqReDamIPezCG9DjENDgk2mZK557yoE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Steven Rostedt (VMware)" Subject: [PATCH 5.3 105/112] ftrace: Get a reference counter for the trace_array on filter files Date: Wed, 16 Oct 2019 14:51:37 -0700 Message-Id: <20191016214907.043942126@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191016214844.038848564@linuxfoundation.org> References: <20191016214844.038848564@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Steven Rostedt (VMware) commit 9ef16693aff8137faa21d16ffe65bb9832d24d71 upstream. 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 started referencing the trace_array directly. Cc: stable@vger.kernel.org Fixes: 673feb9d76ab3 ("ftrace: Add :mod: caching infrastructure to trace_array") Signed-off-by: Steven Rostedt (VMware) Signed-off-by: Greg Kroah-Hartman --- kernel/trace/ftrace.c | 27 ++++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-) --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3540,21 +3540,22 @@ ftrace_regex_open(struct ftrace_ops *ops 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 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 /* 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 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 *i 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;