This is a note to let you know that I've just added the patch titled ip: Fix data-races around sysctl_ip_no_pmtu_disc. to the 5.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ip-fix-data-races-around-sysctl_ip_no_pmtu_disc.patch and it can be found in the queue-5.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit bfaef3475afe611117963912146b1afae2291e9b Author: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx> Date: Wed Jul 13 13:51:52 2022 -0700 ip: Fix data-races around sysctl_ip_no_pmtu_disc. [ Upstream commit 0968d2a441bf6afb551fd99e60fa65ed67068963 ] While reading sysctl_ip_no_pmtu_disc, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index 98bc180563d1..8c0a22a5b36c 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -335,7 +335,7 @@ static int inet_create(struct net *net, struct socket *sock, int protocol, inet->hdrincl = 1; } - if (net->ipv4.sysctl_ip_no_pmtu_disc) + if (READ_ONCE(net->ipv4.sysctl_ip_no_pmtu_disc)) inet->pmtudisc = IP_PMTUDISC_DONT; else inet->pmtudisc = IP_PMTUDISC_WANT; diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index c13ceda9ce5d..d8cfa6241c04 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -878,7 +878,7 @@ static bool icmp_unreach(struct sk_buff *skb) * values please see * Documentation/networking/ip-sysctl.rst */ - switch (net->ipv4.sysctl_ip_no_pmtu_disc) { + switch (READ_ONCE(net->ipv4.sysctl_ip_no_pmtu_disc)) { default: net_dbg_ratelimited("%pI4: fragmentation needed and DF set\n", &iph->daddr); diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c index 7d7b7523d126..ef1e6545d869 100644 --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -226,7 +226,7 @@ static int inet6_create(struct net *net, struct socket *sock, int protocol, RCU_INIT_POINTER(inet->mc_list, NULL); inet->rcv_tos = 0; - if (net->ipv4.sysctl_ip_no_pmtu_disc) + if (READ_ONCE(net->ipv4.sysctl_ip_no_pmtu_disc)) inet->pmtudisc = IP_PMTUDISC_DONT; else inet->pmtudisc = IP_PMTUDISC_WANT; diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index b749935152ba..b4ce16a934a2 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -2620,7 +2620,7 @@ int __xfrm_init_state(struct xfrm_state *x, bool init_replay, bool offload) int err; if (family == AF_INET && - xs_net(x)->ipv4.sysctl_ip_no_pmtu_disc) + READ_ONCE(xs_net(x)->ipv4.sysctl_ip_no_pmtu_disc)) x->props.flags |= XFRM_STATE_NOPMTUDISC; err = -EPROTONOSUPPORT;