net: Revert "ipv4: fix a deadlock in ip_ra_control"

This reverts commit 1215e51eda.
Since raw_close() is used on every RAW socket destruction,
the changes made by 1215e51eda scale sadly. This clearly
seen on endless unshare(CLONE_NEWNET) test, and cleanup_net()
kwork spends a lot of time waiting for rtnl_lock() introduced
by this commit.

Previous patch moved IP_ROUTER_ALERT out of rtnl_lock(),
so we revert this patch.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Kirill Tkhai 2018-03-22 12:45:22 +03:00 committed by David S. Miller
parent 0526947f9d
commit 128aaa98ad
3 changed files with 9 additions and 5 deletions

View file

@ -594,7 +594,6 @@ static bool setsockopt_needs_rtnl(int optname)
case MCAST_LEAVE_GROUP:
case MCAST_LEAVE_SOURCE_GROUP:
case MCAST_UNBLOCK_SOURCE:
case IP_ROUTER_ALERT:
return true;
}
return false;

View file

@ -1399,7 +1399,7 @@ static void mrtsock_destruct(struct sock *sk)
struct net *net = sock_net(sk);
struct mr_table *mrt;
ASSERT_RTNL();
rtnl_lock();
ipmr_for_each_table(mrt, net) {
if (sk == rtnl_dereference(mrt->mroute_sk)) {
IPV4_DEVCONF_ALL(net, MC_FORWARDING)--;
@ -1411,6 +1411,7 @@ static void mrtsock_destruct(struct sock *sk)
mroute_clean_tables(mrt, false);
}
}
rtnl_unlock();
}
/* Socket options and virtual interface manipulation. The whole
@ -1475,8 +1476,13 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, char __user *optval,
if (sk != rcu_access_pointer(mrt->mroute_sk)) {
ret = -EACCES;
} else {
/* We need to unlock here because mrtsock_destruct takes
* care of rtnl itself and we can't change that due to
* the IP_ROUTER_ALERT setsockopt which runs without it.
*/
rtnl_unlock();
ret = ip_ra_control(sk, 0, NULL);
goto out_unlock;
goto out;
}
break;
case MRT_ADD_VIF:
@ -1588,6 +1594,7 @@ int ip_mroute_setsockopt(struct sock *sk, int optname, char __user *optval,
}
out_unlock:
rtnl_unlock();
out:
return ret;
}

View file

@ -711,9 +711,7 @@ static void raw_close(struct sock *sk, long timeout)
/*
* Raw sockets may have direct kernel references. Kill them.
*/
rtnl_lock();
ip_ra_control(sk, 0, NULL);
rtnl_unlock();
sk_common_release(sk);
}