From fc489055e7e8abe409224ff18863999cede92fbf Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Fri, 15 Jul 2022 10:17:45 -0700 Subject: [PATCH] tcp: Fix data-races around keepalive sysctl knobs. [ Upstream commit f2f316e287e6c2e3a1c5bab8d9b77ee03daa0463 ] While reading sysctl_tcp_keepalive_(time|probes|intvl), they can be changed concurrently. Thus, we need to add READ_ONCE() to their readers. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- include/net/tcp.h | 9 ++++++--- net/smc/smc_llc.c | 2 +- 2 files changed, 7 insertions(+), 4 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index 2a28e0925573..9ef9fd0677b5 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1447,21 +1447,24 @@ static inline int keepalive_intvl_when(const struct tcp_sock *tp) { struct net *net = sock_net((struct sock *)tp); - return tp->keepalive_intvl ? : net->ipv4.sysctl_tcp_keepalive_intvl; + return tp->keepalive_intvl ? : + READ_ONCE(net->ipv4.sysctl_tcp_keepalive_intvl); } static inline int keepalive_time_when(const struct tcp_sock *tp) { struct net *net = sock_net((struct sock *)tp); - return tp->keepalive_time ? : net->ipv4.sysctl_tcp_keepalive_time; + return tp->keepalive_time ? : + READ_ONCE(net->ipv4.sysctl_tcp_keepalive_time); } static inline int keepalive_probes(const struct tcp_sock *tp) { struct net *net = sock_net((struct sock *)tp); - return tp->keepalive_probes ? : net->ipv4.sysctl_tcp_keepalive_probes; + return tp->keepalive_probes ? : + READ_ONCE(net->ipv4.sysctl_tcp_keepalive_probes); } static inline u32 keepalive_time_elapsed(const struct tcp_sock *tp) diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c index ee1f0fdba085..0ef15f8fba90 100644 --- a/net/smc/smc_llc.c +++ b/net/smc/smc_llc.c @@ -1787,7 +1787,7 @@ void smc_llc_lgr_init(struct smc_link_group *lgr, struct smc_sock *smc) init_waitqueue_head(&lgr->llc_flow_waiter); init_waitqueue_head(&lgr->llc_msg_waiter); mutex_init(&lgr->llc_conf_mutex); - lgr->llc_testlink_time = net->ipv4.sysctl_tcp_keepalive_time; + lgr->llc_testlink_time = READ_ONCE(net->ipv4.sysctl_tcp_keepalive_time); } /* called after lgr was removed from lgr_list */