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Hi Alexandre,
Thanks for locating the problem.
I don't remember the exact reason that I removed the waitpid call in ipvs
syncd in Feburary and considered it is superfluous, maybe because the
sys_wait4 is not exported on some architecture. I'll use your program to
do a test soon, and see if there is a better solution.
Thanks,
Wensong
On Tue, 17 Aug 2004, Alexandre Cassen wrote:
> Hello Wensong,
>
> I received since last few months lot of bug report from Keepalived users
> using VRRP with ipvs syncd option. Finally today, I found time to look at
> this issue and have a patch for syncd code.
>
> While starting a kernel syncd thread, we must reap the fork_sync_thread
> since this will produce zombies while returning to main calling point.
> Since syncd parent is the init process, we don't need to reap it during the
> syncd shutdown but we must reap it at starting time.
>
> You will find bellow a patch to fixe this and a quick trash C code to argue
> and highlight the need. The patch is against 2.6.7, same patch must be
> applied to 2.4 branch.
>
> Best regards,
> Alexandre
>
>
>
> --[ Patch: Begin Snip ]--
>
> diff -urN linux-2.6.7.orig/net/ipv4/ipvs/ip_vs_sync.c
> linux-2.6.7/net/ipv4/ipvs/ip_vs_sync.c
> --- linux-2.6.7.orig/net/ipv4/ipvs/ip_vs_sync.c 2004-06-16
> 07:18:38.000000000 +0200
> +++ linux-2.6.7/net/ipv4/ipvs/ip_vs_sync.c 2004-08-17
> 18:30:36.143940704 +0200
> @@ -18,9 +18,11 @@
> * messages filtering.
> */
>
> +#define __KERNEL_SYSCALLS__ /* for waitpid */
> +
> #include <linux/module.h>
> #include <linux/slab.h>
> -#include <linux/net.h>
> +#include <linux/unistd.h>
> #include <linux/completion.h>
>
> #include <linux/skbuff.h>
> @@ -612,6 +614,7 @@
> return len;
> }
>
> +static int errno;
>
> static DECLARE_WAIT_QUEUE_HEAD(sync_wait);
> static pid_t sync_master_pid = 0;
> @@ -840,6 +843,7 @@
> int start_sync_thread(int state, char *mcast_ifn, __u8 syncid)
> {
> DECLARE_COMPLETION(startup);
> + int waitpid_result;
> pid_t pid;
>
> if ((state == IP_VS_STATE_MASTER && sync_master_pid) ||
> @@ -868,6 +872,15 @@
> goto repeat;
> }
>
> + /*
> + * We must reap the fork_sync_thread here. Really needed to not
> + * produce zombies while returning.
> + */
> + if ((waitpid_result = waitpid(pid, NULL, __WCLONE)) != pid) {
> + IP_VS_ERR("%s: waitpid(%d,...) failed, errno %d\n",
> + __FUNCTION__, pid, -waitpid_result);
> + }
> +
> wait_for_completion(&startup);
>
> return 0;
>
> --[ Patch: End Snip ]--
>
>
>
> --[ Quick Code: Begin Snip ]--
>
> /*
> * Soft: Simple IPVS Syncd probing tool.
> *
> * Compilation: gcc -I/usr/src/linux/include main.c -o syncd_zombies
> *
> * Version: $Id: main.c,v 0.0.1 2004/08/17 21:35:41 acassen Exp $
> *
> * Authors: Alexandre Cassen, <acassen@xxxxxxxxxxxx>
> *
> * This program is distributed in the hope that it will be
> useful,
> * but WITHOUT ANY WARRANTY; without even the implied warranty
> of
> * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
> * See the GNU General Public License for more details.
> *
> * This program is free software; you can redistribute it and/or
> * modify it under the terms of the GNU General Public License
> * as published by the Free Software Foundation; either version
> * 2 of the License, or (at your option) any later version.
> *
> * Copyright (C) 2001-2004 Alexandre Cassen, <acassen@xxxxxxxxxxxx>
> */
>
> #include <stdio.h>
> #include <unistd.h>
> #include <stdlib.h>
> #include <string.h>
> #include <sys/wait.h>
> #include <sys/socket.h>
> #include <netinet/in.h>
> #include <net/ip_vs.h>
>
> static struct ip_vs_daemon_user *daemonrule;
> static int sockfd = -1;
> static void *ipvs_func = NULL;
> struct ip_vs_getinfo ipvs_info;
> typedef struct ip_vs_daemon_user ipvs_daemon_t;
>
> int
> ipvs_init(void)
> {
> socklen_t len;
>
> len = sizeof (ipvs_info);
> if ((sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) == -1)
> return -1;
>
> if (getsockopt(sockfd, IPPROTO_IP, IP_VS_SO_GET_INFO,
> (char *) &ipvs_info, &len))
> return -1;
>
> return 0;
> }
>
> int
> ipvs_start_daemon(ipvs_daemon_t * dm)
> {
> ipvs_func = ipvs_start_daemon;
> return setsockopt(sockfd, IPPROTO_IP, IP_VS_SO_SET_STARTDAEMON,
> (char *) dm, sizeof (*dm));
> }
>
> extern int
> ipvs_stop_daemon(ipvs_daemon_t * dm)
> {
> ipvs_func = ipvs_stop_daemon;
> return setsockopt(sockfd, IPPROTO_IP, IP_VS_SO_SET_STOPDAEMON,
> (char *) dm, sizeof (*dm));
> }
>
> static int
> modprobe_ipvs(void)
> {
> char *argv[] = { "/sbin/modprobe", "-s", "-k", "--", "ip_vs", NULL };
> int child;
> int status;
> int rc;
>
> if (!(child = fork())) {
> execv(argv[0], argv);
> exit(1);
> }
>
> rc = waitpid(child, &status, 0);
> if (!WIFEXITED(status) || WEXITSTATUS(status))
> return 1;
> return 0;
> }
>
> static void
> ipvs_talk(int cmd)
> {
> int result = -1;
>
> switch (cmd) {
> case IP_VS_SO_SET_STARTDAEMON:
> result = ipvs_start_daemon(daemonrule);
> break;
> case IP_VS_SO_SET_STOPDAEMON:
> result = ipvs_stop_daemon(daemonrule);
> break;
> }
> }
>
> static int
> ipvs_start(void)
> {
> if (ipvs_init()) {
> if (modprobe_ipvs() || ipvs_init()) {
> printf("IPVS: Can't initialize IPVS !!!\n");
> return -1;
> }
> }
> return 0;
> }
>
> int
> ipvs_syncd_cmd(int cmd, char *ifname, int state)
> {
> memset(daemonrule, 0, sizeof (struct ip_vs_daemon_user));
> daemonrule->state = state;
> strncpy(daemonrule->mcast_ifn, ifname, IP_VS_IFNAME_MAXLEN);
> ipvs_talk(cmd);
> return 0;
> }
>
> int
> main(int argc, char **argv)
> {
> daemonrule = (struct ip_vs_daemon_user *) malloc(sizeof (struct
> ip_vs_daemon_user));
>
> ipvs_start();
> ipvs_syncd_cmd(IP_VS_SO_SET_STARTDAEMON, "eth0", IP_VS_STATE_MASTER);
> ipvs_syncd_cmd(IP_VS_SO_SET_STOPDAEMON, "eth0", IP_VS_STATE_MASTER);
> ipvs_syncd_cmd(IP_VS_SO_SET_STARTDAEMON, "eth0", IP_VS_STATE_BACKUP);
> ipvs_syncd_cmd(IP_VS_SO_SET_STOPDAEMON, "eth0", IP_VS_STATE_BACKUP);
>
> free(daemonrule);
>
> for (;;) { /* Dummy loop */ }
> exit(0);
> }
>
> --[ Quick Code: End Snip ]--
>
>
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