Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge branch 'tcp-tcp_tx_timestamp-fix'
Eric Dumazet says:
====================
tcp: tcp_tx_timestamp() fix
Fix an old bug in tcp_tx_timestamp().
Add one corresponding packetdrill test.
====================
Link: https://patch.msgid.link/20260127123828.4098577-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
+73
+3
net/ipv4/tcp.c
+3
net/ipv4/tcp.c
···
501
501
struct sk_buff *skb = tcp_write_queue_tail(sk);
502
502
u32 tsflags = sockc->tsflags;
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+
if (unlikely(!skb))
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+
skb = skb_rb_last(&sk->tcp_rtx_queue);
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+
504
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if (tsflags && skb) {
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struct skb_shared_info *shinfo = skb_shinfo(skb);
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struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
+70
tools/testing/selftests/net/packetdrill/tcp_timestamping_tcp_tx_timestamp_bug.pkt
+70
tools/testing/selftests/net/packetdrill/tcp_timestamping_tcp_tx_timestamp_bug.pkt
···
1
+
// SPDX-License-Identifier: GPL-2.0
2
+
// Test after "tcp: tcp_tx_timestamp() must look at the rtx queue"
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+
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+
// This test is about receiving the SCM_TSTAMP_ACK,
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// we do not care about its SCM_TIMESTAMPING precision.
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--tolerance_usecs=1000000
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+
8
+
`./defaults.sh
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sysctl -q net.ipv4.tcp_min_tso_segs=70
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`
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+
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+
// Create a socket and set it to non-blocking.
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0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
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+
+0 fcntl(3, F_GETFL) = 0x2 (flags O_RDWR)
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+
+0 fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0
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+
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+
// Establish connection and verify that there was no error.
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+
+0 connect(3, ..., ...) = -1 EINPROGRESS (Operation now in progress)
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+
+0 > S 0:0(0) <mss 1460,sackOK,TS val 100 ecr 0,nop,wscale 8>
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+
+.010 < S. 0:0(0) ack 1 win 65535 <mss 1000,sackOK,TS val 700 ecr 100,nop,wscale 7>
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+
+0 > . 1:1(0) ack 1 <nop,nop,TS val 200 ecr 700>
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+
+0 getsockopt(3, SOL_SOCKET, SO_ERROR, [0], [4]) = 0
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+
+0 setsockopt(3, SOL_SOCKET, SO_SNDBUF, [30000], 4) = 0
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+
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+
+0 write(3, ..., 9880) = 9880
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+
+0 > P. 1:9881(9880) ack 1 <nop,nop,TS val 200 ecr 700>
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+
+.010 < . 1:1(0) ack 9881 win 10000 <nop,nop,TS val 701 ecr 200>
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+
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+
+0 write(3, ..., 19760) = 19760
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+
+0 > P. 9881:29641(19760) ack 1 <nop,nop,TS val 201 ecr 701>
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+
+.010 < . 1:1(0) ack 29641 win 10000 <nop,nop,TS val 702 ecr 201>
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+
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+
+0 write(3, ..., 39520) = 39520
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+
+0 > P. 29641:69161(39520) ack 1 <nop,nop,TS val 202 ecr 702>
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+
+.010 < . 1:1(0) ack 69161 win 10000 <nop,nop,TS val 703 ecr 202>
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+
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+
// One more write to increase cwnd
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+
+0 write(3, ..., 79040) = 79040
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+
+0 > P. 69161:108681(39520) ack 1 <nop,nop,TS val 203 ecr 703>
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+
+0 > P. 108681:148201(39520) ack 1 <nop,nop,TS val 203 ecr 703>
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+
+.010 < . 1:1(0) ack 148201 win 1000 <nop,nop,TS val 704 ecr 203>
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+
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+
+0 setsockopt(3, SOL_SOCKET, SO_TIMESTAMPING,
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[SOF_TIMESTAMPING_TX_ACK | SOF_TIMESTAMPING_SOFTWARE |
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+
SOF_TIMESTAMPING_OPT_ID], 4) = 0
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+
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+
// We have one write filling one skb
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+
// last byte can not be stored because of our small SO_SNDBUF
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+
+0 write(3, ..., 65209) = 65208
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+
+0 > P. 148201:213409(65208) ack 1 <nop,nop,TS val 204 ecr 704>
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+
+.010 < . 1:1(0) ack 213409 win 1000 <nop,nop,TS val 705 ecr 204>
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+
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+
// SCM_TSTAMP_ACK should be received after the last ack at
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+
// t=60ms.
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+
+0 recvmsg(3, {msg_name(...)=...,
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+
msg_iov(1)=[{...,0}],
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+
msg_flags=MSG_ERRQUEUE|MSG_TRUNC,
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+
msg_control=[
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+
{cmsg_level=SOL_SOCKET,
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+
cmsg_type=SCM_TIMESTAMPING,
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+
cmsg_data={scm_sec=0,scm_nsec=60000000}},
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+
{cmsg_level=CMSG_LEVEL_IP,
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+
cmsg_type=CMSG_TYPE_RECVERR,
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+
cmsg_data={ee_errno=ENOMSG,
65
+
ee_origin=SO_EE_ORIGIN_TIMESTAMPING,
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+
ee_type=0,
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+
ee_code=0,
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+
ee_info=SCM_TSTAMP_ACK,
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+
ee_data=65207}}
70
+
]}, MSG_ERRQUEUE) = 0