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author | Denis V. Lunev <den@openvz.org> | 2008-01-18 23:55:19 -0800 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2008-01-28 15:08:08 -0800 |
commit | 775516bfa2bd7993620c9039191a0c30b8d8a496 (patch) | |
tree | 7385f35edda9f4124b802ccf337c55070d2e00bc /net/netlink/af_netlink.c | |
parent | b7c6ba6eb1234e35a74fb8ba8123232a7b1ba9e4 (diff) | |
download | kernel_samsung_smdk4412-775516bfa2bd7993620c9039191a0c30b8d8a496.zip kernel_samsung_smdk4412-775516bfa2bd7993620c9039191a0c30b8d8a496.tar.gz kernel_samsung_smdk4412-775516bfa2bd7993620c9039191a0c30b8d8a496.tar.bz2 |
[NETNS]: Namespace stop vs 'ip r l' race.
During network namespace stop process kernel side netlink sockets
belonging to a namespace should be closed. They should not prevent
namespace to stop, so they do not increment namespace usage
counter. Though this counter will be put during last sock_put.
The raplacement of the correct netns for init_ns solves the problem
only partial as socket to be stoped until proper stop is a valid
netlink kernel socket and can be looked up by the user processes. This
is not a problem until it resides in initial namespace (no processes
inside this net), but this is not true for init_net.
So, hold the referrence for a socket, remove it from lookup tables and
only after that change namespace and perform a last put.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Tested-by: Alexey Dobriyan <adobriyan@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/netlink/af_netlink.c')
-rw-r--r-- | net/netlink/af_netlink.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 626a582..6b178e1 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -1396,6 +1396,9 @@ netlink_kernel_create(struct net *net, int unit, unsigned int groups, } netlink_table_ungrab(); + /* Do not hold an extra referrence to a namespace as this socket is + * internal to a namespace and does not prevent it to stop. */ + put_net(net); return sk; out_sock_release: @@ -1411,7 +1414,19 @@ netlink_kernel_release(struct sock *sk) { if (sk == NULL || sk->sk_socket == NULL) return; + + /* + * Last sock_put should drop referrence to sk->sk_net. It has already + * been dropped in netlink_kernel_create. Taking referrence to stopping + * namespace is not an option. + * Take referrence to a socket to remove it from netlink lookup table + * _alive_ and after that destroy it in the context of init_net. + */ + sock_hold(sk); sock_release(sk->sk_socket); + + sk->sk_net = get_net(&init_net); + sock_put(sk); } EXPORT_SYMBOL(netlink_kernel_release); |