linux/net/ipv4
David Ahern 51161aa98d net: Fix suspicious RCU usage in fib_rebalance
This command:
  ip route add 192.168.1.0/24 nexthop via 10.2.1.5 dev eth1 nexthop via 10.2.2.5 dev eth2

generated this suspicious RCU usage message:

[ 63.249262]
[ 63.249939] ===============================
[ 63.251571] [ INFO: suspicious RCU usage. ]
[ 63.253250] 4.3.0-rc3+ #298 Not tainted
[ 63.254724] -------------------------------
[ 63.256401] ../include/linux/inetdevice.h:205 suspicious rcu_dereference_check() usage!
[ 63.259450]
[ 63.259450] other info that might help us debug this:
[ 63.259450]
[ 63.262297]
[ 63.262297] rcu_scheduler_active = 1, debug_locks = 1
[ 63.264647] 1 lock held by ip/2870:
[ 63.265896] #0: (rtnl_mutex){+.+.+.}, at: [<ffffffff813ebfb7>] rtnl_lock+0x12/0x14
[ 63.268858]
[ 63.268858] stack backtrace:
[ 63.270409] CPU: 4 PID: 2870 Comm: ip Not tainted 4.3.0-rc3+ #298
[ 63.272478] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[ 63.275745] 0000000000000001 ffff8800b8c9f8b8 ffffffff8125f73c ffff88013afcf301
[ 63.278185] ffff8800bab7a380 ffff8800b8c9f8e8 ffffffff8107bf30 ffff8800bb728000
[ 63.280634] ffff880139fe9a60 0000000000000000 ffff880139fe9a00 ffff8800b8c9f908
[ 63.283177] Call Trace:
[ 63.283959] [<ffffffff8125f73c>] dump_stack+0x4c/0x68
[ 63.285593] [<ffffffff8107bf30>] lockdep_rcu_suspicious+0xfa/0x103
[ 63.287500] [<ffffffff8144d752>] __in_dev_get_rcu+0x48/0x4f
[ 63.289169] [<ffffffff8144d797>] fib_rebalance+0x3e/0x127
[ 63.290753] [<ffffffff8144d986>] ? rcu_read_unlock+0x3e/0x5f
[ 63.292442] [<ffffffff8144ea45>] fib_create_info+0xaf9/0xdcc
[ 63.294093] [<ffffffff8106c12f>] ? sched_clock_local+0x12/0x75
[ 63.295791] [<ffffffff8145236a>] fib_table_insert+0x8c/0x451
[ 63.297493] [<ffffffff8144bf9c>] ? fib_get_table+0x36/0x43
[ 63.299109] [<ffffffff8144c3ca>] inet_rtm_newroute+0x43/0x51
[ 63.300709] [<ffffffff813ef684>] rtnetlink_rcv_msg+0x182/0x195
[ 63.302334] [<ffffffff8107d04c>] ? trace_hardirqs_on+0xd/0xf
[ 63.303888] [<ffffffff813ebfb7>] ? rtnl_lock+0x12/0x14
[ 63.305346] [<ffffffff813ef502>] ? __rtnl_unlock+0x12/0x12
[ 63.306878] [<ffffffff81407c4c>] netlink_rcv_skb+0x3d/0x90
[ 63.308437] [<ffffffff813ec00e>] rtnetlink_rcv+0x21/0x28
[ 63.309916] [<ffffffff81407742>] netlink_unicast+0xfa/0x17f
[ 63.311447] [<ffffffff81407a5e>] netlink_sendmsg+0x297/0x2dc
[ 63.313029] [<ffffffff813c6cd4>] sock_sendmsg_nosec+0x12/0x1d
[ 63.314597] [<ffffffff813c835b>] ___sys_sendmsg+0x196/0x21b
[ 63.316125] [<ffffffff8100bf9f>] ? native_sched_clock+0x1f/0x3c
[ 63.317671] [<ffffffff8106c12f>] ? sched_clock_local+0x12/0x75
[ 63.319185] [<ffffffff8106c397>] ? sched_clock_cpu+0x9d/0xb6
[ 63.320693] [<ffffffff8107e2d7>] ? __lock_is_held+0x32/0x54
[ 63.322145] [<ffffffff81159fcb>] ? __fget_light+0x4b/0x77
[ 63.323541] [<ffffffff813c8726>] __sys_sendmsg+0x3d/0x5b
[ 63.324947] [<ffffffff813c8751>] SyS_sendmsg+0xd/0x19
[ 63.326274] [<ffffffff814c8f57>] entry_SYSCALL_64_fastpath+0x12/0x6f

It looks like all of the code paths to fib_rebalance are under rtnl.

Fixes: 0e884c78ee ("ipv4: L3 hash-based multipath")
Cc: Peter Nørlund <pch@ordbogen.com>
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-10-16 00:57:55 -07:00
..
netfilter ipv4: Pass struct net into ip_defrag and ip_check_defrag 2015-10-12 19:44:16 -07:00
af_inet.c net: Replace vrf_dev_table and friends 2015-09-29 20:40:33 -07:00
ah4.c ah4: Fix error return in ah_input(). 2015-08-25 13:38:50 -07:00
arp.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-09-26 16:08:27 -07:00
cipso_ipv4.c ipv4: coding style: comparison for inequality with NULL 2015-04-03 12:11:15 -04:00
datagram.c net: Set sk_txhash from a random number 2015-07-29 22:44:04 -07:00
devinet.c rtnetlink: RTEXT_FILTER_SKIP_STATS support to avoid dumping inet/inet6 stats 2015-09-15 15:25:02 -07:00
esp4.c esp4: Switch to new AEAD interface 2015-05-28 11:23:20 +08:00
fib_frontend.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-10-02 07:21:25 -07:00
fib_lookup.h ipv4: consider TOS in fib_select_default 2015-07-24 22:46:11 -07:00
fib_rules.c net: ipv6: use common fib_default_rule_pref 2015-09-09 14:19:50 -07:00
fib_semantics.c net: Fix suspicious RCU usage in fib_rebalance 2015-10-16 00:57:55 -07:00
fib_trie.c net: Fix vti use case with oif in dst lookups 2015-09-17 16:36:34 -07:00
fou.c fou: reject IPv6 config 2015-08-29 13:07:54 -07:00
gre_demux.c gre: Remove support for sharing GRE protocol hook. 2015-08-10 14:03:54 -07:00
gre_offload.c ipv4: coding style: comparison for inequality with NULL 2015-04-03 12:11:15 -04:00
icmp.c Revert "ipv4/icmp: redirect messages can use the ingress daddr as source" 2015-10-14 06:01:07 -07:00
igmp.c ipv4, ipv6: Pass net into ip_local_out and ip6_local_out 2015-10-08 04:27:02 -07:00
inet_connection_sock.c tcp/dccp: fix race at listener dismantle phase 2015-10-16 00:52:19 -07:00
inet_diag.c tcp/dccp: install syn_recv requests into ehash table 2015-10-03 04:32:41 -07:00
inet_fragment.c inet: frags: remove INET_FRAG_EVICTED and use list_evictor for the test 2015-07-26 21:00:15 -07:00
inet_hashtables.c tcp/dccp: fix potential NULL deref in __inet_inherit_port() 2015-10-14 19:06:31 -07:00
inet_lro.c
inet_timewait_sock.c tcp/dccp: fix timewait races in timer handling 2015-09-21 16:32:29 -07:00
inetpeer.c net: Add helper function to compare inetpeer addresses 2015-08-28 13:32:36 -07:00
ip_forward.c net: Pass net into dst_output and remove dst_output_okfn 2015-10-08 04:26:54 -07:00
ip_fragment.c ipv4: Pass struct net into ip_defrag and ip_check_defrag 2015-10-12 19:44:16 -07:00
ip_gre.c ip_tunnels: record IP version in tunnel info 2015-08-29 13:07:54 -07:00
ip_input.c ipv4: Pass struct net into ip_defrag and ip_check_defrag 2015-10-12 19:44:16 -07:00
ip_options.c ipv4: coding style: comparison for inequality with NULL 2015-04-03 12:11:15 -04:00
ip_output.c dst: Pass net into dst->output 2015-10-08 04:27:03 -07:00
ip_sockglue.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2015-06-24 02:58:51 -07:00
ip_tunnel_core.c ipv4, ipv6: Pass net into ip_local_out and ip6_local_out 2015-10-08 04:27:02 -07:00
ip_tunnel.c ip_gre: Add support to collect tunnel metadata. 2015-08-10 14:03:54 -07:00
ip_vti.c net: Pass net into dst_output and remove dst_output_okfn 2015-10-08 04:26:54 -07:00
ipcomp.c ipv4: coding style: comparison for equality with NULL 2015-04-03 12:11:15 -04:00
ipconfig.c net: ipv4: increase dhcp inter device timeout 2015-08-12 16:40:22 -07:00
ipip.c ip_gre: Add support to collect tunnel metadata. 2015-08-10 14:03:54 -07:00
ipmr.c net: Pass net into dst_output and remove dst_output_okfn 2015-10-08 04:26:54 -07:00
Kconfig geneve: Consolidate Geneve functionality in single module. 2015-08-27 15:42:48 -07:00
Makefile geneve: Consolidate Geneve functionality in single module. 2015-08-27 15:42:48 -07:00
netfilter.c ipv4: Pass struct net into ip_route_me_harder 2015-09-29 20:21:32 +02:00
ping.c ipv6: Nonlocal bind 2015-07-09 21:09:10 -07:00
proc.c net: track success and failure of TCP PMTU probing 2015-07-21 22:36:33 -07:00
protocol.c
raw.c net: Pass net into dst_output and remove dst_output_okfn 2015-10-08 04:26:54 -07:00
route.c net: Do not drop to make_route if oif is l3mdev 2015-10-08 05:18:47 -07:00
syncookies.c net: shrink struct sock and request_sock by 8 bytes 2015-10-12 19:28:22 -07:00
sysctl_net_ipv4.c Revert "ipv4/icmp: redirect messages can use the ingress daddr as source" 2015-10-14 06:01:07 -07:00
tcp_bic.c tcp: add tcp_in_slow_start helper 2015-07-09 14:22:52 -07:00
tcp_cdg.c tcp: do not slow start when cwnd equals ssthresh 2015-07-09 14:22:52 -07:00
tcp_cong.c tcp: remove tcp_ecn_make_synack() socket argument 2015-09-25 13:00:38 -07:00
tcp_cubic.c tcp_cubic: do not set epoch_start in the future 2015-09-17 22:35:07 -07:00
tcp_dctcp.c net: tcp: dctcp_update_alpha() fixes. 2015-06-10 23:28:33 -07:00
tcp_diag.c sock_diag: implement a get_info handler for inet 2015-06-15 19:49:22 -07:00
tcp_fastopen.c tcp: fix fastopen races vs lockless listener 2015-10-05 02:45:24 -07:00
tcp_highspeed.c tcp: add tcp_in_slow_start helper 2015-07-09 14:22:52 -07:00
tcp_htcp.c tcp: add tcp_in_slow_start helper 2015-07-09 14:22:52 -07:00
tcp_hybla.c tcp: do not slow start when cwnd equals ssthresh 2015-07-09 14:22:52 -07:00
tcp_illinois.c tcp: add tcp_in_slow_start helper 2015-07-09 14:22:52 -07:00
tcp_input.c net: shrink struct sock and request_sock by 8 bytes 2015-10-12 19:28:22 -07:00
tcp_ipv4.c tcp/dccp: add inet_csk_reqsk_queue_drop_and_put() helper 2015-10-16 00:52:18 -07:00
tcp_lp.c
tcp_memcontrol.c
tcp_metrics.c net: Add helper function to compare inetpeer addresses 2015-08-28 13:32:36 -07:00
tcp_minisocks.c net: shrink struct sock and request_sock by 8 bytes 2015-10-12 19:28:22 -07:00
tcp_offload.c tcp: reserve tcp_skb_mss() to tcp stack 2015-06-11 16:33:10 -07:00
tcp_output.c net: shrink struct sock and request_sock by 8 bytes 2015-10-12 19:28:22 -07:00
tcp_probe.c
tcp_scalable.c tcp: add tcp_in_slow_start helper 2015-07-09 14:22:52 -07:00
tcp_timer.c tcp: change type of alive from int to bool 2015-10-12 05:15:03 -07:00
tcp_vegas.c tcp: add tcp_in_slow_start helper 2015-07-09 14:22:52 -07:00
tcp_vegas.h tcp: prepare CC get_info() access from getsockopt() 2015-04-29 17:10:38 -04:00
tcp_veno.c tcp: add tcp_in_slow_start helper 2015-07-09 14:22:52 -07:00
tcp_westwood.c tcp_westwood: fix tcp_westwood_info() 2015-05-05 19:50:09 -04:00
tcp_yeah.c
tcp.c net: ipv4: tcp.c Fixed an assignment coding style issue 2015-10-07 05:01:04 -07:00
tunnel4.c
udp_diag.c sock_diag: specify info_size per inet protocol 2015-06-15 19:49:22 -07:00
udp_impl.h
udp_offload.c ipv4: coding style: comparison for inequality with NULL 2015-04-03 12:11:15 -04:00
udp_tunnel.c tunnel: introduce udp_tun_rx_dst() 2015-08-27 15:42:47 -07:00
udp.c net: SO_INCOMING_CPU setsockopt() support 2015-10-12 19:28:20 -07:00
udplite.c
xfrm4_input.c netfilter: Pass net into okfn 2015-09-17 17:18:37 -07:00
xfrm4_mode_beet.c
xfrm4_mode_transport.c
xfrm4_mode_tunnel.c ipv4: hash net ptr into fragmentation bucket selection 2015-03-25 14:07:04 -04:00
xfrm4_output.c dst: Pass net into dst->output 2015-10-08 04:27:03 -07:00
xfrm4_policy.c ipv4: Merge __ip_local_out and __ip_local_out_sk 2015-10-08 04:26:57 -07:00
xfrm4_protocol.c
xfrm4_state.c
xfrm4_tunnel.c