linux-stable/net/ipv4
Pengcheng Yang 07667c9475 tcp: fix marked lost packets not being retransmitted
[ Upstream commit e176b1ba47 ]

When the packet pointed to by retransmit_skb_hint is unlinked by ACK,
retransmit_skb_hint will be set to NULL in tcp_clean_rtx_queue().
If packet loss is detected at this time, retransmit_skb_hint will be set
to point to the current packet loss in tcp_verify_retransmit_hint(),
then the packets that were previously marked lost but not retransmitted
due to the restriction of cwnd will be skipped and cannot be
retransmitted.

To fix this, when retransmit_skb_hint is NULL, retransmit_skb_hint can
be reset only after all marked lost packets are retransmitted
(retrans_out >= lost_out), otherwise we need to traverse from
tcp_rtx_queue_head in tcp_xmit_retransmit_queue().

Packetdrill to demonstrate:

// Disable RACK and set max_reordering to keep things simple
    0 `sysctl -q net.ipv4.tcp_recovery=0`
   +0 `sysctl -q net.ipv4.tcp_max_reordering=3`

// Establish a connection
   +0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
   +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
   +0 bind(3, ..., ...) = 0
   +0 listen(3, 1) = 0

  +.1 < S 0:0(0) win 32792 <mss 1000,sackOK,nop,nop,nop,wscale 7>
   +0 > S. 0:0(0) ack 1 <...>
 +.01 < . 1:1(0) ack 1 win 257
   +0 accept(3, ..., ...) = 4

// Send 8 data segments
   +0 write(4, ..., 8000) = 8000
   +0 > P. 1:8001(8000) ack 1

// Enter recovery and 1:3001 is marked lost
 +.01 < . 1:1(0) ack 1 win 257 <sack 3001:4001,nop,nop>
   +0 < . 1:1(0) ack 1 win 257 <sack 5001:6001 3001:4001,nop,nop>
   +0 < . 1:1(0) ack 1 win 257 <sack 5001:7001 3001:4001,nop,nop>

// Retransmit 1:1001, now retransmit_skb_hint points to 1001:2001
   +0 > . 1:1001(1000) ack 1

// 1001:2001 was ACKed causing retransmit_skb_hint to be set to NULL
 +.01 < . 1:1(0) ack 2001 win 257 <sack 5001:8001 3001:4001,nop,nop>
// Now retransmit_skb_hint points to 4001:5001 which is now marked lost

// BUG: 2001:3001 was not retransmitted
   +0 > . 2001:3001(1000) ack 1

Signed-off-by: Pengcheng Yang <yangpc@wangsu.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Tested-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-23 08:22:51 +01:00
..
bpfilter SPDX update for 5.2-rc2, round 1 2019-05-21 12:33:38 -07:00
netfilter netfilter: arp_tables: init netns pointer in xt_tgdtor_param struct 2020-01-23 08:22:47 +01:00
af_inet.c net: remove empty inet_exit_net 2019-08-19 18:22:54 -07:00
ah4.c xfrm: remove type and offload_type map from xfrm_state_afinfo 2019-06-06 08:34:50 +02:00
arp.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cipso_ipv4.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13 2019-05-21 11:28:45 +02:00
datagram.c inet: stop leaking jiffies on the wire 2019-11-01 14:57:52 -07:00
devinet.c inet: protect against too small mtu values. 2019-12-18 16:08:17 +01:00
esp4.c xfrm: remove get_mtu indirection from xfrm_type 2019-07-01 06:16:40 +02:00
esp4_offload.c Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next 2019-07-05 15:01:15 -07:00
fib_frontend.c ipv4: fix route update on metric change. 2019-10-26 11:25:53 -07:00
fib_lookup.h ipv4: Use accessors for fib_info nexthop data 2019-06-04 19:26:49 -07:00
fib_notifier.c
fib_rules.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-07 11:00:14 -07:00
fib_semantics.c ipv4: Fix table id reference in fib_sync_down_addr 2019-11-07 16:14:36 -08:00
fib_trie.c net: route dump netlink NLM_F_MULTI flag missing 2019-08-24 16:49:48 -07:00
fou.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
gre_demux.c gre: refetch erspan header from skb->data after pskb_may_pull() 2019-12-18 16:08:51 +01:00
gre_offload.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
icmp.c net: icmp: fix data-race in cmp_global_allow() 2020-01-04 19:18:40 +01:00
igmp.c net: fix __ip_mc_inc_group usage 2019-08-20 12:48:06 -07:00
inet_connection_sock.c net: add bool confirm_neigh parameter for dst_ops.update_pmtu 2020-01-04 19:18:58 +01:00
inet_diag.c tcp/dccp: fix possible race __inet_lookup_established() 2020-01-04 19:19:13 +01:00
inet_fragment.c inet: frags: re-introduce skb coalescing for local delivery 2019-08-08 15:55:10 -07:00
inet_hashtables.c tcp/dccp: fix possible race __inet_lookup_established() 2020-01-04 19:19:13 +01:00
inet_timewait_sock.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
inetpeer.c inetpeer: fix data-race in inet_putpeer / inet_putpeer 2020-01-04 19:18:39 +01:00
ip_forward.c ipv4: Revert removal of rt_uses_gateway 2019-09-20 18:23:33 -07:00
ip_fragment.c inet: frags: re-introduce skb coalescing for local delivery 2019-08-08 15:55:10 -07:00
ip_gre.c erspan: fix the tun_info options_len check for erspan 2019-10-29 17:36:42 -07:00
ip_input.c netfilter: drop bridge nf reset from nf_reset 2019-10-01 18:42:15 +02:00
ip_options.c netfilter: nf_tables: add support for matching IPv4 options 2019-06-21 18:35:51 +02:00
ip_output.c inet: protect against too small mtu values. 2019-12-18 16:08:17 +01:00
ip_sockglue.c ip_sockglue: Fix missing-check bug in ip_ra_control() 2019-05-25 11:00:50 -07:00
ip_tunnel.c tunnel: do not confirm neighbor when do pmtu update 2020-01-04 19:19:02 +01:00
ip_tunnel_core.c ip_tunnel: allow not to count pkts on tstats by setting skb's dev to NULL 2019-06-18 20:48:45 -04:00
ip_vti.c vti: do not confirm neighbor when do pmtu update 2020-01-04 19:19:03 +01:00
ipcomp.c Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next 2019-07-05 15:01:15 -07:00
ipconfig.c ipconfig: add carrier_timeout kernel parameter 2019-02-01 15:24:13 -08:00
ipip.c ipip: validate header length in ipip_tunnel_xmit 2019-07-25 17:23:40 -07:00
ipmr.c ipmr: Fix skb headroom in ipmr_get_route(). 2019-11-16 13:06:54 -08:00
ipmr_base.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-05-07 17:22:09 -07:00
Kconfig net: Fix Kconfig indentation 2019-09-26 08:56:17 +02:00
Makefile net: Initial nexthop code 2019-05-28 21:37:30 -07:00
metrics.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
netfilter.c netfilter: ipv4: remove useless export_symbol 2019-01-28 11:32:58 +01:00
netlink.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
nexthop.c nexthops: remove redundant assignment to variable err 2019-08-22 12:14:05 -07:00
ping.c ip: support SO_MARK cmsg 2019-09-13 21:44:19 +02:00
proc.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-17 20:20:36 -07:00
protocol.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
raw.c netfilter: drop bridge nf reset from nf_reset 2019-10-01 18:42:15 +02:00
raw_diag.c net: don't warn in inet diag when IPV6 is disabled 2019-07-03 11:26:35 -07:00
route.c net: add bool confirm_neigh parameter for dst_ops.update_pmtu 2020-01-04 19:18:58 +01:00
syncookies.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
sysctl_net_ipv4.c net/ipv4: fix sysctl max for fib_multipath_hash_policy 2019-11-18 17:25:36 -08:00
tcp.c tcp: fix data-race in tcp_recvmsg() 2020-01-09 10:19:54 +01:00
tcp_bbr.c net: annotate lockless accesses to sk->sk_pacing_shift 2020-01-09 10:20:07 +01:00
tcp_bic.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
tcp_bpf.c bpf/sockmap: Read psock ingress_msg before sk_receive_queue 2020-01-23 08:22:47 +01:00
tcp_cdg.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
tcp_cong.c tcp: fix tcp_set_congestion_control() use from bpf hook 2019-07-18 20:33:48 -07:00
tcp_cubic.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
tcp_dctcp.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
tcp_dctcp.h
tcp_diag.c tcp: annotate tp->write_seq lockless reads 2019-10-13 10:13:08 -07:00
tcp_fastopen.c tcp: add rcu protection around tp->fastopen_rsk 2019-10-13 10:13:08 -07:00
tcp_highspeed.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
tcp_htcp.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
tcp_hybla.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
tcp_illinois.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
tcp_input.c tcp: fix marked lost packets not being retransmitted 2020-01-23 08:22:51 +01:00
tcp_ipv4.c tcp/dccp: fix possible race __inet_lookup_established() 2020-01-04 19:19:13 +01:00
tcp_lp.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
tcp_metrics.c tcp: refactor setting the initial congestion window 2019-05-01 11:47:54 -04:00
tcp_minisocks.c tcp: annotate tp->snd_nxt lockless reads 2019-10-13 10:13:08 -07:00
tcp_nv.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
tcp_offload.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
tcp_output.c net: annotate lockless accesses to sk->sk_pacing_shift 2020-01-09 10:20:07 +01:00
tcp_rate.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
tcp_recovery.c
tcp_scalable.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
tcp_timer.c tcp: add rcu protection around tp->fastopen_rsk 2019-10-13 10:13:08 -07:00
tcp_ulp.c bpf: Sockmap/tls, push write_space updates through ulp updates 2020-01-23 08:22:45 +01:00
tcp_vegas.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
tcp_vegas.h
tcp_veno.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
tcp_westwood.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
tcp_yeah.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
tunnel4.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
udp.c udp: fix integer overflow while computing available space in sk_rcvbuf 2020-01-04 19:18:49 +01:00
udp_diag.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
udp_impl.h udp: add missing rehash callback to udplite 2019-01-17 15:01:08 -08:00
udp_offload.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-22 08:59:24 -04:00
udp_tunnel.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
udplite.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
xfrm4_input.c
xfrm4_output.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
xfrm4_policy.c net: add bool confirm_neigh parameter for dst_ops.update_pmtu 2020-01-04 19:18:58 +01:00
xfrm4_protocol.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
xfrm4_state.c xfrm: remove eth_proto value from xfrm_state_afinfo 2019-06-06 08:34:50 +02:00
xfrm4_tunnel.c xfrm: remove type and offload_type map from xfrm_state_afinfo 2019-06-06 08:34:50 +02:00