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 28592C0015E for ; Thu, 13 Jul 2023 14:48:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231794AbjGMOsD (ORCPT ); Thu, 13 Jul 2023 10:48:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54030 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231126AbjGMOr6 (ORCPT ); Thu, 13 Jul 2023 10:47:58 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A443D19A6; Thu, 13 Jul 2023 07:47:57 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 40477615BE; Thu, 13 Jul 2023 14:47:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2CAF6C433C8; Thu, 13 Jul 2023 14:47:56 +0000 (UTC) Date: Thu, 13 Jul 2023 10:47:54 -0400 From: Steven Rostedt To: Zheng Yejian Cc: , , Subject: Re: [PATCH] traing: Fix memory leak of iter->temp when reading trace_pipe Message-ID: <20230713104754.6cf4696c@gandalf.local.home> In-Reply-To: References: <20230713141435.1133021-1-zhengyejian1@huawei.com> X-Mailer: Claws Mail 3.19.1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org On Thu, 13 Jul 2023 22:23:20 +0800 Zheng Yejian wrote: > On 2023/7/13 22:14, Zheng Yejian wrote: > > kmemleak reports: > > unreferenced object 0xffff88814d14e200 (size 256): > > comm "cat", pid 336, jiffies 4294871818 (age 779.490s) > > hex dump (first 32 bytes): > > 04 00 01 03 00 00 00 00 08 00 00 00 00 00 00 00 ................ > > 0c d8 c8 9b ff ff ff ff 04 5a ca 9b ff ff ff ff .........Z...... > > backtrace: > > [] __kmalloc+0x4f/0x140 > > [] trace_find_next_entry+0xbb/0x1d0 > > [] trace_print_lat_context+0xaf/0x4e0 > > [] print_trace_line+0x3e0/0x950 > > [] tracing_read_pipe+0x2d9/0x5a0 > > [] vfs_read+0x143/0x520 > > [] ksys_read+0xbd/0x160 > > [] do_syscall_64+0x3f/0x90 > > [] entry_SYSCALL_64_after_hwframe+0x6e/0xd8 > > > > when reading file 'trace_pipe', 'iter->temp' is allocated or relocated > > in trace_find_next_entry() but not freed before 'trace_pipe' is closed. > > > > To fix it, free 'iter->temp' in tracing_release_pipe(). > > > > Sorry, forget the Fixes tag:( > > Is following Fixes right? > Fixes: ff895103a84a ("tracing: Save off entry when peeking at next entry") That's the one I already added ;-) Don't worry too much about adding fixes, I will always analyze a fix patch to find out what it actually fixes. If you add one, I'll still confirm it. -- Steve > > > Signed-off-by: Zheng Yejian > > --- > > kernel/trace/trace.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > > index 4529e264cb86..94cfaa884578 100644 > > --- a/kernel/trace/trace.c > > +++ b/kernel/trace/trace.c > > @@ -6764,6 +6764,7 @@ static int tracing_release_pipe(struct inode *inode, struct file *file) > > > > free_cpumask_var(iter->started); > > kfree(iter->fmt); > > + kfree(iter->temp); > > mutex_destroy(&iter->mutex); > > kfree(iter); > >