[PATCH 1/3] IPVS: Change of socket usage to enable name space exit.

[Hans Schillstrom <hans@xxxxxxxxxxxxxxx>]

This is the first patch in a series of three.
The cleanup doesn't work when not exit in a clean way by using ipvsadm.
Killing of a namespace causes a hanging ipvs, this series will cure that.

If the sync daemons run in a namespace while it crashes
or get killed, there is no way to stop them except for a reboot.

Kernel threads should not increment the use count of a socket.
By calling sk_change_net() after creating a socket this is avoided.
sock_release cant be used, instead sk_release_kernel() should be used.

Thanks to Eric W Biederman.

This patch is based on net-next-2.6  ver 2.6.39-rc2

Signed-off-by: Hans Schillstrom <hans@xxxxxxxxxxxxxxx>
---
 net/netfilter/ipvs/ip_vs_sync.c |   28 +++++++++++++++++++---------
 1 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/net/netfilter/ipvs/ip_vs_sync.c b/net/netfilter/ipvs/ip_vs_sync.c
index 3e7961e..3f87555 100644
--- a/net/netfilter/ipvs/ip_vs_sync.c
+++ b/net/netfilter/ipvs/ip_vs_sync.c
@@ -1309,7 +1309,12 @@ static struct socket *make_send_sock(struct net *net)
                pr_err("Error during creation of socket; terminating\n");
                return ERR_PTR(result);
        }
-
+       /*
+        * Kernel sockets that are a part of a namespace, should not
+        * hold a reference to a namespace in order to allow to stop it.
+        * After sk_change_net should be released using sk_release_kernel.
+        */
+       sk_change_net(sock->sk, net);
        result = set_mcast_if(sock->sk, ipvs->master_mcast_ifn);
        if (result < 0) {
                pr_err("Error setting outbound mcast interface\n");
@@ -1334,8 +1339,8 @@ static struct socket *make_send_sock(struct net *net)

        return sock;

-  error:
-       sock_release(sock);
+error:
+       sk_release_kernel(sock->sk);
        return ERR_PTR(result);
 }

@@ -1355,7 +1360,12 @@ static struct socket *make_receive_sock(struct net *net)
                pr_err("Error during creation of socket; terminating\n");
                return ERR_PTR(result);
        }
-
+       /*
+        * Kernel sockets that are a part of a namespace, should not
+        * hold a reference to a namespace in order to allow to stop it.
+        * After sk_change_net should be released using sk_release_kernel.
+        */
+       sk_change_net(sock->sk, net);
        /* it is equivalent to the REUSEADDR option in user-space */
        sock->sk->sk_reuse = 1;

@@ -1377,8 +1387,8 @@ static struct socket *make_receive_sock(struct net *net)

        return sock;

-  error:
-       sock_release(sock);
+error:
+       sk_release_kernel(sock->sk);
        return ERR_PTR(result);
 }

@@ -1473,7 +1483,7 @@ static int sync_thread_master(void *data)
                ip_vs_sync_buff_release(sb);

        /* release the sending multicast socket */
-       sock_release(tinfo->sock);
+       sk_release_kernel(tinfo->sock->sk);
        kfree(tinfo);

        return 0;
@@ -1513,7 +1523,7 @@ static int sync_thread_backup(void *data)
        }

        /* release the sending multicast socket */
-       sock_release(tinfo->sock);
+       sk_release_kernel(tinfo->sock->sk);
        kfree(tinfo->buf);
        kfree(tinfo);

@@ -1601,7 +1611,7 @@ outtinfo:
 outbuf:
        kfree(buf);
 outsocket:
-       sock_release(sock);
+       sk_release_kernel(sock->sk);
 out:
        return result;
 }
--
1.7.2.3

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