The branch main has been updated by rscheff: URL: https://cgit.FreeBSD.org/src/commit/?id=68e623c3f0afb4c9b338046fd1d4476befd82324
commit 68e623c3f0afb4c9b338046fd1d4476befd82324 Author: Richard Scheffenegger <[email protected]> AuthorDate: 2022-01-27 17:35:47 +0000 Commit: Richard Scheffenegger <[email protected]> CommitDate: 2022-01-27 17:49:42 +0000 tcp: Rewind erraneous RTO only while performing RTO retransmissions Under rare circumstances, a spurious retranmission is incorrectly detected and rewound, messing up various tcpcb values, which can lead to a panic when SACK is in use. Reviewed By: tuexen, chengc_netapp.com, #transport MFC after: 3 days Sponsored by: NetApp, Inc. Differential Revision: https://reviews.freebsd.org/D33979 --- sys/netinet/tcp_input.c | 1 + sys/netinet/tcp_var.h | 6 +++++- 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c index 110cb99df7bb..d6d193d18213 100644 --- a/sys/netinet/tcp_input.c +++ b/sys/netinet/tcp_input.c @@ -1649,6 +1649,7 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so, if (TSTMP_GT(to.to_tsecr, tcp_ts_getticks())) to.to_tsecr = 0; else if (tp->t_flags & TF_PREVVALID && + tp->t_rxtshift == 1 && tp->t_badrxtwin != 0 && SEQ_LT(to.to_tsecr, tp->t_badrxtwin)) cc_cong_signal(tp, th, CC_RTO_ERR); } diff --git a/sys/netinet/tcp_var.h b/sys/netinet/tcp_var.h index e9d021fb4684..07788ada3985 100644 --- a/sys/netinet/tcp_var.h +++ b/sys/netinet/tcp_var.h @@ -506,7 +506,11 @@ tcp_unlock_or_drop(struct tcpcb *tp, int tcp_output_retval) #define TF_NEEDSYN 0x00000400 /* send SYN (implicit state) */ #define TF_NEEDFIN 0x00000800 /* send FIN (implicit state) */ #define TF_NOPUSH 0x00001000 /* don't push */ -#define TF_PREVVALID 0x00002000 /* saved values for bad rxmit valid */ +#define TF_PREVVALID 0x00002000 /* saved values for bad rxmit valid + * Note: accessing and restoring from + * these may only be done in the 1st + * RTO recovery round (t_rxtshift == 1) + */ #define TF_WAKESOR 0x00004000 /* wake up receive socket */ #define TF_GPUTINPROG 0x00008000 /* Goodput measurement in progress */ #define TF_MORETOCOME 0x00010000 /* More data to be appended to sock */
