remarkable-linux/net/dccp
Eric Dumazet 7716682cc5 tcp/dccp: fix another race at listener dismantle
Ilya reported following lockdep splat:

kernel: =========================
kernel: [ BUG: held lock freed! ]
kernel: 4.5.0-rc1-ceph-00026-g5e0a311 #1 Not tainted
kernel: -------------------------
kernel: swapper/5/0 is freeing memory
ffff880035c9d200-ffff880035c9dbff, with a lock still held there!
kernel: (&(&queue->rskq_lock)->rlock){+.-...}, at:
[<ffffffff816f6a88>] inet_csk_reqsk_queue_add+0x28/0xa0
kernel: 4 locks held by swapper/5/0:
kernel: #0:  (rcu_read_lock){......}, at: [<ffffffff8169ef6b>]
netif_receive_skb_internal+0x4b/0x1f0
kernel: #1:  (rcu_read_lock){......}, at: [<ffffffff816e977f>]
ip_local_deliver_finish+0x3f/0x380
kernel: #2:  (slock-AF_INET){+.-...}, at: [<ffffffff81685ffb>]
sk_clone_lock+0x19b/0x440
kernel: #3:  (&(&queue->rskq_lock)->rlock){+.-...}, at:
[<ffffffff816f6a88>] inet_csk_reqsk_queue_add+0x28/0xa0

To properly fix this issue, inet_csk_reqsk_queue_add() needs
to return to its callers if the child as been queued
into accept queue.

We also need to make sure listener is still there before
calling sk->sk_data_ready(), by holding a reference on it,
since the reference carried by the child can disappear as
soon as the child is put on accept queue.

Reported-by: Ilya Dryomov <idryomov@gmail.com>
Fixes: ebb516af60 ("tcp/dccp: fix race at listener dismantle phase")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-18 11:35:51 -05:00
..
ccids
ackvec.c dccp: drop null test before destroy functions 2015-09-15 16:49:43 -07:00
ackvec.h
ccid.c dccp: drop null test before destroy functions 2015-09-15 16:49:43 -07:00
ccid.h
dccp.h tcp/dccp: fix hashdance race for passive sessions 2015-10-23 05:42:21 -07:00
diag.c sock_diag: specify info_size per inet protocol 2015-06-15 19:49:22 -07:00
feat.c
feat.h
input.c
ipv4.c tcp/dccp: fix another race at listener dismantle 2016-02-18 11:35:51 -05:00
ipv6.c tcp/dccp: fix another race at listener dismantle 2016-02-18 11:35:51 -05:00
ipv6.h
Kconfig
Makefile
minisocks.c tcp/dccp: fix hashdance race for passive sessions 2015-10-23 05:42:21 -07:00
options.c
output.c net: Generalise wq_has_sleeper helper 2015-11-30 14:47:33 -05:00
probe.c Use 64-bit timekeeping 2015-11-01 17:01:16 -05:00
proto.c net: rename SOCK_ASYNC_NOSPACE and SOCK_ASYNC_WAITDATA 2015-12-01 15:45:05 -05:00
qpolicy.c
sysctl.c
timer.c inet: get rid of central tcp/dccp listener timer 2015-03-20 12:40:25 -04:00