* [PATCH net] tcp: annotate data races around tp->mtu_info
@ 2021-07-02 20:09 Eric Dumazet
2021-07-02 20:40 ` patchwork-bot+netdevbpf
0 siblings, 1 reply; 2+ messages in thread
From: Eric Dumazet @ 2021-07-02 20:09 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski; +Cc: netdev, Eric Dumazet, Eric Dumazet
From: Eric Dumazet <edumazet@google.com>
While tp->mtu_info is read while socket is owned, the write
sides happen from err handlers (tcp_v[46]_mtu_reduced)
which only own the socket spinlock.
Fixes: 563d34d05786 ("tcp: dont drop MTU reduction indications")
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
net/ipv4/tcp_ipv4.c | 4 ++--
net/ipv6/tcp_ipv6.c | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index e66ad6bfe8083bfde66d24d9644abcdb649508be..b9dc2d6197be8b8b03a4d052ad1c87987c7a62aa 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -342,7 +342,7 @@ void tcp_v4_mtu_reduced(struct sock *sk)
if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
return;
- mtu = tcp_sk(sk)->mtu_info;
+ mtu = READ_ONCE(tcp_sk(sk)->mtu_info);
dst = inet_csk_update_pmtu(sk, mtu);
if (!dst)
return;
@@ -546,7 +546,7 @@ int tcp_v4_err(struct sk_buff *skb, u32 info)
if (sk->sk_state == TCP_LISTEN)
goto out;
- tp->mtu_info = info;
+ WRITE_ONCE(tp->mtu_info, info);
if (!sock_owned_by_user(sk)) {
tcp_v4_mtu_reduced(sk);
} else {
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 578ab6305c3f84819bb38054acf1e62c00a9061e..593c32fe57ed13a218492fd6056f2593e601ec79 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -352,7 +352,7 @@ static void tcp_v6_mtu_reduced(struct sock *sk)
if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
return;
- dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info);
+ dst = inet6_csk_update_pmtu(sk, READ_ONCE(tcp_sk(sk)->mtu_info));
if (!dst)
return;
@@ -443,7 +443,7 @@ static int tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
if (!ip6_sk_accept_pmtu(sk))
goto out;
- tp->mtu_info = ntohl(info);
+ WRITE_ONCE(tp->mtu_info, ntohl(info));
if (!sock_owned_by_user(sk))
tcp_v6_mtu_reduced(sk);
else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,
--
2.32.0.93.g670b81a890-goog
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH net] tcp: annotate data races around tp->mtu_info
2021-07-02 20:09 [PATCH net] tcp: annotate data races around tp->mtu_info Eric Dumazet
@ 2021-07-02 20:40 ` patchwork-bot+netdevbpf
0 siblings, 0 replies; 2+ messages in thread
From: patchwork-bot+netdevbpf @ 2021-07-02 20:40 UTC (permalink / raw)
To: Eric Dumazet; +Cc: davem, kuba, netdev, edumazet
Hello:
This patch was applied to netdev/net.git (refs/heads/master):
On Fri, 2 Jul 2021 13:09:03 -0700 you wrote:
> From: Eric Dumazet <edumazet@google.com>
>
> While tp->mtu_info is read while socket is owned, the write
> sides happen from err handlers (tcp_v[46]_mtu_reduced)
> which only own the socket spinlock.
>
> Fixes: 563d34d05786 ("tcp: dont drop MTU reduction indications")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
>
> [...]
Here is the summary with links:
- [net] tcp: annotate data races around tp->mtu_info
https://git.kernel.org/netdev/net/c/561022acb1ce
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 2+ messages in thread
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2021-07-02 20:40 ` patchwork-bot+netdevbpf
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