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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 66F96C4321A for ; Fri, 28 Jun 2019 13:35:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 300AB2147A for ; Fri, 28 Jun 2019 13:35:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561728906; bh=NK7VdWZqj61oGMb7hOSZNcUxWzYCDi723Oci2tLSdBQ=; h=Subject:From:To:Cc:Date:In-Reply-To:References:List-ID:From; b=1FctAKm5kKqnb2t7U95Q20CClYwKqv9mZSw+GPQcUVj59BLHKvLh1DtKI4WsdGLIq EQZOBRvi0VGHfh9q4NsMOIcqNwSAPPluDlUGVCslilhPKJPYrv50Cfx6fdbxMHEN63 JSf5XMRYPZAgp6Ktayg6n/ue62syl83Hkz/0VdIo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726723AbfF1NfE (ORCPT ); Fri, 28 Jun 2019 09:35:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:39486 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726669AbfF1NfE (ORCPT ); Fri, 28 Jun 2019 09:35:04 -0400 Received: from tzanussi-mobl (c-98-220-238-81.hsd1.il.comcast.net [98.220.238.81]) (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 9C6AF208E3; Fri, 28 Jun 2019 13:35:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561728904; bh=NK7VdWZqj61oGMb7hOSZNcUxWzYCDi723Oci2tLSdBQ=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=HrlX0lesqTCm+/fJVu0E4yRRUJ+soSBltekK4jUjqbIZjTW2DcZRd985IeBqC94jX eGyqW6PutiXw/Ba+ZxiuhS5PRU57vzG8HKx+fk4/odLWdLKhr4qfrbTkkl2fydwIB1 CGaQg94QmU2j6NvKfTB8OxGB7enne7VngyMchuyo= Message-ID: <1561728902.9333.2.camel@kernel.org> Subject: Re: [PATCH v2] tracing: Fix memory leak in tracing_err_log_open() From: Tom Zanussi To: Takeshi Misawa , Steven Rostedt Cc: Ingo Molnar , linux-kernel@vger.kernel.org Date: Fri, 28 Jun 2019 08:35:02 -0500 In-Reply-To: <20190628105640.GA1863@DESKTOP> References: <20190628105640.GA1863@DESKTOP> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.1-1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Fri, 2019-06-28 at 19:56 +0900, Takeshi Misawa wrote: > If tracing_err_log_open() call seq_open(), allocated memory is not > freed. > > kmemleak report: > > unreferenced object 0xffff92c0781d1100 (size 128): > comm "tail", pid 15116, jiffies 4295163855 (age 22.704s) > hex dump (first 32 bytes): > 00 f0 08 e5 c0 92 ff ff 00 10 00 00 00 00 00 00 ................ > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > backtrace: > [<000000000d0687d5>] kmem_cache_alloc+0x11f/0x1e0 > [<000000003e3039a8>] seq_open+0x2f/0x90 > [<000000008dd36b7d>] tracing_err_log_open+0x67/0x140 > [<000000005a431ae2>] do_dentry_open+0x1df/0x3a0 > [<00000000a2910603>] vfs_open+0x2f/0x40 > [<0000000038b0a383>] path_openat+0x2e8/0x1690 > [<00000000fe025bda>] do_filp_open+0x9b/0x110 > [<00000000483a5091>] do_sys_open+0x1ba/0x260 > [<00000000c558b5fd>] __x64_sys_openat+0x20/0x30 > [<000000006881ec07>] do_syscall_64+0x5a/0x130 > [<00000000571c2e94>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > Fix this by calling seq_release() in tracing_err_log_fops.release(). > > Signed-off-by: Takeshi Misawa > --- > Dear Steven Rostedt > > Thanks for reviewing. > > > Actually, I think it is safer to have the condition be: > > > > if (file->f_mode & FMODE_READ) > > > > As that would match the open. > > > > Can you send a v2? > > I send a v2 patch. > > Regards. > --- > kernel/trace/trace.c | 14 +++++++++++++- > 1 file changed, 13 insertions(+), 1 deletion(-) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index 83e08b78dbee..4122ccde6ec2 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -7126,12 +7126,24 @@ static ssize_t tracing_err_log_write(struct > file *file, > return count; > } > > +static int tracing_err_log_release(struct inode *inode, struct file > *file) > +{ > + struct trace_array *tr = inode->i_private; > + > + trace_array_put(tr); > + > + if (file->f_mode & FMODE_READ) > + seq_release(inode, file); > + > + return 0; > +} > + > static const struct file_operations tracing_err_log_fops = { > .open = tracing_err_log_open, > .write = tracing_err_log_write, > .read = seq_read, > .llseek = seq_lseek, > - .release = tracing_release_generic_tr, > + .release = tracing_err_log_release, > }; > v2 looks good to me, thanks for sending this fix. Reviewed-by: Tom Zanussi > static int tracing_buffers_open(struct inode *inode, struct file > *filp)