5.15-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ Upstream commit fde6f897f2a184546bf5516ac736523ef24dc6a7 ]
These functions have races when they:
1) Write sk->sk_err 2) call sk_error_report(sk) 3) call tcp_done(sk)
As described in prior patches in this series:
An smp_wmb() is missing. We should call tcp_done() before sk_error_report(sk) to have consistent tcp_poll() results on SMP hosts.
Use tcp_done_with_error() where we centralized the correct sequence.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet edumazet@google.com Acked-by: Neal Cardwell ncardwell@google.com Link: https://lore.kernel.org/r/20240528125253.1966136-5-edumazet@google.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/ipv4/tcp_ipv4.c | 11 +++-------- net/ipv6/tcp_ipv6.c | 10 +++------- 2 files changed, 6 insertions(+), 15 deletions(-)
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index a1ed81ff9a81d..44a9fa957301b 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -592,15 +592,10 @@ int tcp_v4_err(struct sk_buff *skb, u32 info)
ip_icmp_error(sk, skb, err, th->dest, info, (u8 *)th);
- if (!sock_owned_by_user(sk)) { - WRITE_ONCE(sk->sk_err, err); - - sk_error_report(sk); - - tcp_done(sk); - } else { + if (!sock_owned_by_user(sk)) + tcp_done_with_error(sk, err); + else WRITE_ONCE(sk->sk_err_soft, err); - } goto out; }
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index c9aee34ae469f..fedbce7ed853e 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -485,14 +485,10 @@ static int tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
ipv6_icmp_error(sk, skb, err, th->dest, ntohl(info), (u8 *)th);
- if (!sock_owned_by_user(sk)) { - WRITE_ONCE(sk->sk_err, err); - sk_error_report(sk); /* Wake people up to see the error (see connect in sock.c) */ - - tcp_done(sk); - } else { + if (!sock_owned_by_user(sk)) + tcp_done_with_error(sk, err); + else WRITE_ONCE(sk->sk_err_soft, err); - } goto out; case TCP_LISTEN: break;