WSL2-Linux-Kernel/net
Eric Dumazet e0f9759f53 tcp: try to keep packet if SYN_RCV race is lost
배석진 reported that in some situations, packets for a given 5-tuple
end up being processed by different CPUS.

This involves RPS, and fragmentation.

배석진 is seeing packet drops when a SYN_RECV request socket is
moved into ESTABLISH state. Other states are protected by socket lock.

This is caused by a CPU losing the race, and simply not caring enough.

Since this seems to occur frequently, we can do better and perform
a second lookup.

Note that all needed memory barriers are already in the existing code,
thanks to the spin_lock()/spin_unlock() pair in inet_ehash_insert()
and reqsk_put(). The second lookup must find the new socket,
unless it has already been accepted and closed by another cpu.

Note that the fragmentation could be avoided in the first place by
use of a correct TCP MSS option in the SYN{ACK} packet, but this
does not mean we can not be more robust.

Many thanks to 배석진 for a very detailed analysis.

Reported-by: 배석진 <soukjin.bae@samsung.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-14 14:21:45 -05:00
..
6lowpan License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
9p vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
802 treewide: setup_timer() -> timer_setup() 2017-11-21 15:57:07 -08:00
8021q net: delete /proc THIS_MODULE references 2018-01-16 15:01:33 -05:00
appletalk net: make getname() functions return length rather than use int* parameter 2018-02-12 14:15:04 -05:00
atm net: make getname() functions return length rather than use int* parameter 2018-02-12 14:15:04 -05:00
ax25 net: make getname() functions return length rather than use int* parameter 2018-02-12 14:15:04 -05:00
batman-adv vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
bluetooth net: make getname() functions return length rather than use int* parameter 2018-02-12 14:15:04 -05:00
bpf bpf: fix null pointer deref in bpf_prog_test_run_xdp 2018-02-01 07:43:56 -08:00
bridge net: bridge: Fix uninitialized error in br_fdb_sync_static() 2018-02-01 09:47:37 -05:00
caif vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
can net: make getname() functions return length rather than use int* parameter 2018-02-12 14:15:04 -05:00
ceph libceph: check kstrndup() return value 2018-01-29 18:36:12 +01:00
core net: Make dn_ptr depend on CONFIG_DECNET 2018-02-14 11:55:33 -05:00
dcb rtnetlink: make rtnl_register accept a flags parameter 2017-08-09 16:57:38 -07:00
dccp vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
decnet net: make getname() functions return length rather than use int* parameter 2018-02-12 14:15:04 -05:00
dns_resolver afs: Support the AFS dynamic root 2018-02-06 14:43:37 +00:00
dsa net: dsa: Support internal phy on 'cpu' port 2018-01-23 19:22:38 -05:00
ethernet networking: make skb_push & __skb_push return void pointers 2017-06-16 11:48:40 -04:00
hsr net: hsr: Convert timers to use timer_setup() 2017-10-25 13:00:27 +09:00
ieee802154 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
ife MAINTAINERS: Update Yotam's E-mail 2017-11-01 12:19:03 +09:00
ipv4 tcp: try to keep packet if SYN_RCV race is lost 2018-02-14 14:21:45 -05:00
ipv6 tcp: try to keep packet if SYN_RCV race is lost 2018-02-14 14:21:45 -05:00
iucv net: make getname() functions return length rather than use int* parameter 2018-02-12 14:15:04 -05:00
kcm vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
key af_key: Fix memory leak in key_notify_policy. 2018-01-10 09:45:11 +01:00
l2tp net: make getname() functions return length rather than use int* parameter 2018-02-12 14:15:04 -05:00
l3mdev
lapb treewide: Remove TIMER_FUNC_TYPE and TIMER_DATA_TYPE casts 2017-11-21 16:35:54 -08:00
llc net: make getname() functions return length rather than use int* parameter 2018-02-12 14:15:04 -05:00
mac80211 debugfs_sta: Remove unneeded semicolons 2018-01-22 14:03:28 +01:00
mac802154 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
mpls mpls, nospec: Sanitize array index in mpls_label_ok() 2018-02-08 15:24:12 -05:00
ncsi net/ncsi: Don't take any action on HNCDSC AEN 2017-12-18 14:50:11 -05:00
netfilter net: Convert nf_log_net_ops 2018-02-13 10:36:06 -05:00
netlabel net/netlabel: Add list_next_rcu() in rcu_dereference(). 2017-11-18 10:32:41 +09:00
netlink net: Convert netlink_tap_net_ops 2018-02-13 10:36:09 -05:00
netrom net: make getname() functions return length rather than use int* parameter 2018-02-12 14:15:04 -05:00
nfc net: make getname() functions return length rather than use int* parameter 2018-02-12 14:15:04 -05:00
nsh openvswitch: enable NSH support 2017-11-08 16:12:33 +09:00
openvswitch openvswitch: Remove padding from packet before L3+ conntrack processing 2018-02-01 09:46:22 -05:00
packet net: Convert packet_net_ops 2018-02-13 10:36:08 -05:00
phonet net: make getname() functions return length rather than use int* parameter 2018-02-12 14:15:04 -05:00
psample MAINTAINERS: Update Yotam's E-mail 2017-11-01 12:19:03 +09:00
qrtr net: make getname() functions return length rather than use int* parameter 2018-02-12 14:15:04 -05:00
rds net: make getname() functions return length rather than use int* parameter 2018-02-12 14:15:04 -05:00
rfkill vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
rose net: make getname() functions return length rather than use int* parameter 2018-02-12 14:15:04 -05:00
rxrpc vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
sched net: Convert subsys_initcall() registered pernet_operations from net/sched 2018-02-13 10:36:07 -05:00
sctp sctp: add file comments in diag.c 2018-02-13 13:56:31 -05:00
smc net: make getname() functions return length rather than use int* parameter 2018-02-12 14:15:04 -05:00
strparser strparser: Call sock_owned_by_user_nocheck 2017-12-28 14:28:22 -05:00
sunrpc net: make getname() functions return length rather than use int* parameter 2018-02-12 14:15:04 -05:00
switchdev net: bridge: Add/del switchdev object on host join/leave 2017-11-10 13:41:40 +09:00
tipc net: make getname() functions return length rather than use int* parameter 2018-02-12 14:15:04 -05:00
tls net: add a UID to use for ULP socket assignment 2018-02-06 11:39:31 +01:00
unix net: Convert unix_net_ops 2018-02-13 10:36:08 -05:00
vmw_vsock net: make getname() functions return length rather than use int* parameter 2018-02-12 14:15:04 -05:00
wimax License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
wireless net: Convert wext_pernet_ops 2018-02-13 10:36:08 -05:00
x25 net: make getname() functions return length rather than use int* parameter 2018-02-12 14:15:04 -05:00
xfrm net: Convert pernet_subsys, registered from inet_init() 2018-02-13 10:36:08 -05:00
Kconfig Staging/IIO patches for 4.16-rc1 2018-02-01 09:51:57 -08:00
Makefile ipx: move Novell IPX protocol support into staging 2017-11-28 13:55:00 +01:00
compat.c net: compat: assert the size of cmsg copied in is as expected 2017-09-20 15:36:18 -07:00
socket.c net: Remove atalk header from socket.c 2018-02-14 11:55:33 -05:00
sysctl_net.c net: Convert sysctl_pernet_ops 2018-02-13 10:36:05 -05:00