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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E217FEB64DC for ; Sat, 15 Jul 2023 05:15:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229657AbjGOFPj (ORCPT ); Sat, 15 Jul 2023 01:15:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49636 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229487AbjGOFPi (ORCPT ); Sat, 15 Jul 2023 01:15:38 -0400 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D11963A9D; Fri, 14 Jul 2023 22:15:35 -0700 (PDT) Received: from dggpeml500012.china.huawei.com (unknown [172.30.72.57]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4R2xNt5JSyz18KHx; Sat, 15 Jul 2023 13:14:54 +0800 (CST) Received: from [10.67.110.218] (10.67.110.218) by dggpeml500012.china.huawei.com (7.185.36.15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.27; Sat, 15 Jul 2023 13:15:32 +0800 Message-ID: Date: Sat, 15 Jul 2023 13:15:32 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.6.0 Subject: Re: [PATCH 2/2] tracing: Add free_trace_iter_content() helper function Content-Language: en-US To: Steven Rostedt , LKML , Linux Trace Kernel CC: Masami Hiramatsu , Mark Rutland References: <20230713114510.04c452ca@gandalf.local.home> <20230713114700.450e7a17@gandalf.local.home> From: Zheng Yejian In-Reply-To: <20230713114700.450e7a17@gandalf.local.home> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.67.110.218] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpeml500012.china.huawei.com (7.185.36.15) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org On 2023/7/13 23:47, Steven Rostedt wrote: > From: "Steven Rostedt (Google)" > > As the trace iterator is created and used by various interfaces, the clean > up of it needs to be consistent. Create a free_trace_iter_content() helper > function that frees the content of the iterator and use that to clean it > up in all places that it is used. > > Signed-off-by: Steven Rostedt (Google) > --- > kernel/trace/trace.c | 40 ++++++++++++++++++++++++++++------------ > 1 file changed, 28 insertions(+), 12 deletions(-) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index 1c370ffbe062..3f38250637e2 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -4815,6 +4815,25 @@ static const struct seq_operations tracer_seq_ops = { > .show = s_show, > }; > > +/* > + * Note, as iter itself can be allocated and freed in different > + * ways, this function is only used to free its content, and not > + * the iterator itself. The only requirement to all the allocations > + * is that it must zero all fields (kzalloc), as freeing works with > + * ethier allocated content or NULL. > + */ > +static void free_trace_iter_content(struct trace_iterator *iter) > +{ > + /* The fmt is either NULL, allocated or points to static_fmt_buf */ > + if (iter->fmt != static_fmt_buf) > + kfree(iter->fmt); > + > + kfree(iter->temp); > + kfree(iter->buffer_iter); > + mutex_destroy(&iter->mutex); > + free_cpumask_var(iter->started); > +} > + > static struct trace_iterator * > __tracing_open(struct inode *inode, struct file *file, bool snapshot) > { > @@ -4922,8 +4941,7 @@ __tracing_open(struct inode *inode, struct file *file, bool snapshot) > > fail: > mutex_unlock(&trace_types_lock); > - kfree(iter->temp); > - kfree(iter->buffer_iter); > + free_trace_iter_content(iter); > release: > seq_release_private(inode, file); > return ERR_PTR(-ENOMEM); > @@ -5002,11 +5020,7 @@ static int tracing_release(struct inode *inode, struct file *file) > > mutex_unlock(&trace_types_lock); > > - mutex_destroy(&iter->mutex); > - free_cpumask_var(iter->started); > - kfree(iter->fmt); > - kfree(iter->temp); > - kfree(iter->buffer_iter); > + free_trace_iter_content(iter); > seq_release_private(inode, file); > > return 0; > @@ -6709,7 +6723,12 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp) > } > > trace_seq_init(&iter->seq); > - iter->trace = tr->current_trace; > + > + iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL); > + if (!iter->trace) > + goto fail; Hi, Steve, 'ret' may need to be set before `goto fail`: ret = -ENOMEM; > + > + *iter->trace = *tr->current_trace; > > if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) { > ret = -ENOMEM; > @@ -6763,10 +6782,7 @@ static int tracing_release_pipe(struct inode *inode, struct file *file) > > mutex_unlock(&trace_types_lock); > > - free_cpumask_var(iter->started); > - kfree(iter->fmt); > - kfree(iter->temp); > - mutex_destroy(&iter->mutex); > + free_trace_iter_content(iter); > kfree(iter); > > trace_array_put(tr);