From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1755180AbcGELlO (ORCPT <rfc822;w@1wt.eu>);
	Tue, 5 Jul 2016 07:41:14 -0400
Received: from szxga03-in.huawei.com ([119.145.14.66]:33576 "EHLO
	szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1755168AbcGELlG (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Tue, 5 Jul 2016 07:41:06 -0400
Message-ID: <577B9CC5.3090404@huawei.com>
Date: Tue, 5 Jul 2016 19:40:53 +0800
From: Xishi Qiu <qiuxishi@huawei.com>
User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:12.0) Gecko/20120428 Thunderbird/12.0.1
MIME-Version: 1.0
To: <oleg@redhat.com>, <ebiederm@xmission.com>
CC: Linux MM <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>
Subject: is pid_namespace leak in v3.10?
Content-Type: text/plain; charset="ISO-8859-1"
Content-Transfer-Encoding: 7bit
X-Originating-IP: [10.177.25.179]
X-CFilter-Loop: Reflected
X-Mirapoint-Virus-RAPID-Raw: score=unknown(0),
	refid=str=0001.0A020205.577B9CCB.01D6,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0,
	ip=0.0.0.0,
	so=2013-05-26 15:14:31,
	dmn=2013-03-21 17:37:32
X-Mirapoint-Loop-Id: db7ba432cec8cc9b9fc87f989793d5b5
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

I find pid_namespace leak by "cat /proc/slabinfo | grep pid_namespace".
The kernel version is RHEL 7.1 (kernel v3.10 stable).
The following is the test case, after several times, the count of pid_namespace
become very large, is it correct?

I also test mainline, and the count will increase too, but it seems stably later.

BTW, this patch doesn't help.
24c037ebf5723d4d9ab0996433cee4f96c292a4d
exit: pidns: alloc_pid() leaks pid_namespace if child_reaper is exiting

Thanks,
Xishi Qiu


#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <signal.h>

#ifndef CLONE_NEWPID
#define CLONE_NEWPID            0x20000000
#endif

void test(void)
{
        printf("clone child\n");
        exit(0);
}

int main()
{
        pid_t pid, child_pid;
        int  i, status;
        void *stack;

        for (i = 0; i < 100; i++) {
                stack = malloc(8192);
                pid = clone(&test, (char *)stack + 8192, CLONE_NEWPID|SIGCHLD, 0);
        }

        sleep(5);

        return 0;
}