On Mon, Jun 13, 2011 at 11:32:10AM +0200, Hans Schillstrom wrote:
> ip_vs_mutext is used by both netns shutdown code and startup
> and both implicit uses sk_lock-AF_INET mutex.
>
> cleanup CPU-1 startup CPU-2
> ip_vs_dst_event() ip_vs_genl_set_cmd()
> sk_lock-AF_INET __ip_vs_mutex
> sk_lock-AF_INET
> __ip_vs_mutex
> * DEAD LOCK *
>
> This can be solved by have the ip_vs_mutex per netns
> or avid locking when starting/stoping sync-threads.
> i.e. just add a starting/stoping flag.
>
> ip_vs_mutex per name-space seems to be a more future proof solution.
>
> Which one should be used ?
I don't feel strongly either way.
> Signed-off-by: Hans Schillstrom <hans.schillstrom@xxxxxxxxxxxx>
> ---
> include/net/ip_vs.h | 2 ++
> net/netfilter/ipvs/ip_vs_ctl.c | 15 ++++++++++-----
> net/netfilter/ipvs/ip_vs_sync.c | 30 +++++++++++++++++++++++++-----
> 3 files changed, 37 insertions(+), 10 deletions(-)
>
[snip]
> diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
> index 699c79a..21c541f 100644
> --- a/net/netfilter/ipvs/ip_vs_ctl.c
> +++ b/net/netfilter/ipvs/ip_vs_ctl.c
[snip]
> @@ -3305,12 +3309,13 @@ static int ip_vs_genl_set_cmd(struct sk_buff *skb, struct genl_info *info)
> ret = -EINVAL;
> goto out;
> }
> -
> + /* Unlock since a global socket lock will be taken later */
> + mutex_unlock(&__ip_vs_mutex);
> if (cmd == IPVS_CMD_NEW_DAEMON)
> ret = ip_vs_genl_new_daemon(net, daemon_attrs);
> else
> ret = ip_vs_genl_del_daemon(net, daemon_attrs);
> - goto out;
> + goto out_nounlock;
I'm not a huge fan of labels that only return.
So I think it would be slightly easier on the eyes
to just return here, not add out_nounlock,
and possibly rename out as out_unlock.
> } else if (cmd == IPVS_CMD_ZERO &&
> !info->attrs[IPVS_CMD_ATTR_SERVICE]) {
> ret = ip_vs_zero_all(net);
[snip]
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