commit b761c9b1f4f69eb53fb6147547a1ab25237a93b3
author Gao feng <gaofeng@cn.fujitsu.com> Wed Jul 04 23:28:40 2012 +0000
committer David S. Miller <davem@davemloft.net> Mon Jul 09 00:18:04 2012 -0700
tree 914b20a973bbffca5fd4e524d2858ff708b56bba
parent b93984c9afacd4fe32b785d52a93660d91202b10

cgroup: fix panic in netprio_cgroup

we set max_prioidx to the first zero bit index of prioidx_map in
function get_prioidx.

So when we delete the low index netprio cgroup and adding a new
netprio cgroup again,the max_prioidx will be set to the low index.

when we set the high index cgroup's net_prio.ifpriomap,the function
write_priomap will call update_netdev_tables to alloc memory which
size is sizeof(struct netprio_map) + sizeof(u32) * (max_prioidx + 1),
so the size of array that map->priomap point to is max_prioidx +1,
which is low than what we actually need.

fix this by adding check in get_prioidx,only set max_prioidx when
max_prioidx low than the new prioidx.

Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>