Eric Dumazet 06f877d613 tcp/dccp: fix other lockdep splats accessing ireq_opt ... In my first attempt to fix the lockdep splat, I forgot we could enter inet_csk_route_req() with a freshly allocated request socket, for which refcount has not yet been elevated, due to complex SLAB_TYPESAFE_BY_RCU rules. We either are in rcu_read_lock() section _or_ we own a refcount on the request. Correct RCU verb to use here is rcu_dereference_check(), although it is not possible to prove we actually own a reference on a shared refcount :/ In v2, I added ireq_opt_deref() helper and use in three places, to fix other possible splats. [ 49.844590] lockdep_rcu_suspicious+0xea/0xf3 [ 49.846487] inet_csk_route_req+0x53/0x14d [ 49.848334] tcp_v4_route_req+0xe/0x10 [ 49.850174] tcp_conn_request+0x31c/0x6a0 [ 49.851992] ? __lock_acquire+0x614/0x822 [ 49.854015] tcp_v4_conn_request+0x5a/0x79 [ 49.855957] ? tcp_v4_conn_request+0x5a/0x79 [ 49.858052] tcp_rcv_state_process+0x98/0xdcc [ 49.859990] ? sk_filter_trim_cap+0x2f6/0x307 [ 49.862085] tcp_v4_do_rcv+0xfc/0x145 [ 49.864055] ? tcp_v4_do_rcv+0xfc/0x145 [ 49.866173] tcp_v4_rcv+0x5ab/0xaf9 [ 49.868029] ip_local_deliver_finish+0x1af/0x2e7 [ 49.870064] ip_local_deliver+0x1b2/0x1c5 [ 49.871775] ? inet_del_offload+0x45/0x45 [ 49.873916] ip_rcv_finish+0x3f7/0x471 [ 49.875476] ip_rcv+0x3f1/0x42f [ 49.876991] ? ip_local_deliver_finish+0x2e7/0x2e7 [ 49.878791] __netif_receive_skb_core+0x6d3/0x950 [ 49.880701] ? process_backlog+0x7e/0x216 [ 49.882589] __netif_receive_skb+0x1d/0x5e [ 49.884122] process_backlog+0x10c/0x216 [ 49.885812] net_rx_action+0x147/0x3df Fixes: a6ca7abe53 ("tcp/dccp: fix lockdep splat in inet_csk_route_req()") Fixes: c92e8c02fe ("tcp/dccp: fix ireq->opt races") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: kernel test robot <fengguang.wu@intel.com> Reported-by: Maciej Żenczykowski <maze@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2017-10-26 17:41:32 +09:00
..
ccids	dccp: do not use tcp_time_stamp	2017-05-17 16:06:01 -04:00
ackvec.c
ackvec.h
ccid.c
ccid.h
dccp.h
diag.c
feat.c	dccp: fix a memleak for dccp_feat_init err process	2017-07-27 00:01:05 -07:00
feat.h
input.c	dccp: make const array error_code static	2017-07-13 09:24:02 -07:00
ipv4.c	tcp/dccp: fix other lockdep splats accessing ireq_opt	2017-10-26 17:41:32 +09:00
ipv6.c	net: dccp: Add handling of IPV6_PKTOPTIONS to dccp_v6_do_rcv()	2017-08-31 11:43:47 -07:00
ipv6.h
Kconfig
Makefile
minisocks.c
options.c	networking: make skb_push & __skb_push return void pointers	2017-06-16 11:48:40 -04:00
output.c
probe.c
proto.c	dccp: defer ccid_hc_tx_delete() at dismantle time	2017-08-16 14:26:26 -07:00
qpolicy.c
sysctl.c
timer.c