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authorEric Dumazet <edumazet@google.com>2021-10-25 09:48:23 -0700
committerJakub Kicinski <kuba@kernel.org>2021-10-25 18:02:13 -0700
commit14834c4f4eb3c8c0af40f6203dbf09d232044d9d (patch)
tree714e8ea9aa75d7e5cc1d7d418401ed3474716dba /net
parent790eb67374d43f66102a80821d22188b6a0bc3bb (diff)
ipv4: annotate data races arount inet->min_ttl
No report yet from KCSAN, yet worth documenting the races. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/ip_sockglue.c5
-rw-r--r--net/ipv4/tcp_ipv4.c7
2 files changed, 9 insertions, 3 deletions
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index b297bb28556e..d5487c858067 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -1352,7 +1352,10 @@ static int do_ip_setsockopt(struct sock *sk, int level, int optname,
goto e_inval;
if (val < 0 || val > 255)
goto e_inval;
- inet->min_ttl = val;
+ /* tcp_v4_err() and tcp_v4_rcv() might read min_ttl
+ * while we are changint it.
+ */
+ WRITE_ONCE(inet->min_ttl, val);
break;
default:
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 2bdc32c1afb6..a9cbc8e6b796 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -508,7 +508,8 @@ int tcp_v4_err(struct sk_buff *skb, u32 info)
if (sk->sk_state == TCP_CLOSE)
goto out;
- if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
+ /* min_ttl can be changed concurrently from do_ip_setsockopt() */
+ if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {
__NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
goto out;
}
@@ -2068,7 +2069,9 @@ process:
return 0;
}
}
- if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
+
+ /* min_ttl can be changed concurrently from do_ip_setsockopt() */
+ if (unlikely(iph->ttl < READ_ONCE(inet_sk(sk)->min_ttl))) {
__NET_INC_STATS(net, LINUX_MIB_TCPMINTTLDROP);
goto discard_and_relse;
}