kernel_optimize_test/include/net
David Ahern 9ed59592e3 lwtunnel: fix autoload of lwt modules
Trying to add an mpls encap route when the MPLS modules are not loaded
hangs. For example:

    CONFIG_MPLS=y
    CONFIG_NET_MPLS_GSO=m
    CONFIG_MPLS_ROUTING=m
    CONFIG_MPLS_IPTUNNEL=m

    $ ip route add 10.10.10.10/32 encap mpls 100 via inet 10.100.1.2

The ip command hangs:
root       880   826  0 21:25 pts/0    00:00:00 ip route add 10.10.10.10/32 encap mpls 100 via inet 10.100.1.2

    $ cat /proc/880/stack
    [<ffffffff81065a9b>] call_usermodehelper_exec+0xd6/0x134
    [<ffffffff81065efc>] __request_module+0x27b/0x30a
    [<ffffffff814542f6>] lwtunnel_build_state+0xe4/0x178
    [<ffffffff814aa1e4>] fib_create_info+0x47f/0xdd4
    [<ffffffff814ae451>] fib_table_insert+0x90/0x41f
    [<ffffffff814a8010>] inet_rtm_newroute+0x4b/0x52
    ...

modprobe is trying to load rtnl-lwt-MPLS:

root       881     5  0 21:25 ?        00:00:00 /sbin/modprobe -q -- rtnl-lwt-MPLS

and it hangs after loading mpls_router:

    $ cat /proc/881/stack
    [<ffffffff81441537>] rtnl_lock+0x12/0x14
    [<ffffffff8142ca2a>] register_netdevice_notifier+0x16/0x179
    [<ffffffffa0033025>] mpls_init+0x25/0x1000 [mpls_router]
    [<ffffffff81000471>] do_one_initcall+0x8e/0x13f
    [<ffffffff81119961>] do_init_module+0x5a/0x1e5
    [<ffffffff810bd070>] load_module+0x13bd/0x17d6
    ...

The problem is that lwtunnel_build_state is called with rtnl lock
held preventing mpls_init from registering.

Given the potential references held by the time lwtunnel_build_state it
can not drop the rtnl lock to the load module. So, extract the module
loading code from lwtunnel_build_state into a new function to validate
the encap type. The new function is called while converting the user
request into a fib_config which is well before any table, device or
fib entries are examined.

Fixes: 745041e2aa ("lwtunnel: autoload of lwt modules")
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-01-18 17:07:14 -05:00
..
9p
bluetooth
caif
irda
iucv
netfilter
netns
nfc
phonet
sctp
tc_act
6lowpan.h
act_api.h
addrconf.h
af_ieee802154.h
af_rxrpc.h
af_unix.h
af_vsock.h
ah.h
arp.h
atmclip.h
ax25.h
ax88796.h
bond_3ad.h
bond_alb.h
bond_options.h
bonding.h
busy_poll.h
calipso.h
cfg80211-wext.h
cfg80211.h
cfg802154.h
checksum.h
cipso_ipv4.h
cls_cgroup.h
codel_impl.h
codel_qdisc.h
codel.h
compat.h
datalink.h
dcbevent.h
dcbnl.h
devlink.h
dn_dev.h
dn_fib.h
dn_neigh.h
dn_nsp.h
dn_route.h
dn.h
dsa.h
dsfield.h
dst_cache.h
dst_metadata.h
dst_ops.h
dst.h
esp.h
ethoc.h
fib_rules.h
firewire.h
flow_dissector.h
flow.h
flowcache.h
fou.h
fq_impl.h
fq.h
garp.h
gen_stats.h
genetlink.h
geneve.h
gre.h
gro_cells.h
gtp.h
gue.h
hwbm.h
icmp.h
ieee80211_radiotap.h
ieee802154_netdev.h
if_inet6.h
ila.h
inet6_connection_sock.h
inet6_hashtables.h
inet_common.h
inet_connection_sock.h
inet_ecn.h
inet_frag.h
inet_hashtables.h
inet_sock.h
inet_timewait_sock.h
inetpeer.h
ip6_checksum.h
ip6_fib.h
ip6_route.h
ip6_tunnel.h
ip_fib.h
ip_tunnels.h
ip_vs.h
ip.h
ipcomp.h
ipconfig.h
ipv6.h
ipx.h
iw_handler.h
kcm.h
l3mdev.h
lapb.h
lib80211.h
llc_c_ac.h
llc_c_ev.h
llc_c_st.h
llc_conn.h
llc_if.h
llc_pdu.h
llc_s_ac.h
llc_s_ev.h
llc_s_st.h
llc_sap.h
llc.h
lwtunnel.h
mac80211.h
mac802154.h
mip6.h
mld.h
mpls_iptunnel.h
mpls.h
mrp.h
ncsi.h
ndisc.h
neighbour.h
net_namespace.h
net_ratelimit.h
netevent.h
netlabel.h
netlink.h
netprio_cgroup.h
netrom.h
nexthop.h
nl802154.h
p8022.h
ping.h
pkt_cls.h
pkt_sched.h
pptp.h
protocol.h
psnap.h
raw.h
rawv6.h
red.h
regulatory.h
request_sock.h
rose.h
route.h
rtnetlink.h
sch_generic.h
scm.h
secure_seq.h
seg6_hmac.h
seg6.h
slhc_vj.h
snmp.h
sock_reuseport.h
sock.h
Space.h
stp.h
strparser.h
switchdev.h
tcp_states.h
tcp.h
timewait_sock.h
transp_v6.h
tso.h
udp_tunnel.h
udp.h
udplite.h
vsock_addr.h
vxlan.h
wext.h
wimax.h
x25.h
x25device.h
xfrm.h