From: Eric Dumazet edumazet@google.com
[ Upstream commit 580f98cc33a260bb8c6a39ae2921b29586b84fdf ]
This is a follow up of commit 0a375c822497 ("tcp: tcp_rtx_synack() can be called from process context").
Frederick Lawler reported another "__this_cpu_add() in preemptible" warning caused by the same reason.
In my former patch I took care of tcp_rtx_synack() but forgot that tcp_check_req() also contained some SNMP updates.
Note that some parts of tcp_check_req() always run in BH context, I added a comment to clarify this.
Fixes: 8336886f786f ("tcp: TCP Fast Open Server - support TFO listeners") Link: https://lore.kernel.org/netdev/8cd33923-a21d-397c-e46b-2a068c287b03@cloudfla... Signed-off-by: Eric Dumazet edumazet@google.com Reported-by: Frederick Lawler fred@cloudflare.com Tested-by: Frederick Lawler fred@cloudflare.com Link: https://lore.kernel.org/r/20230227083336.4153089-1-edumazet@google.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/ipv4/tcp_minisocks.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index 41368e77fbb81..aa67d5adcbca9 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -565,6 +565,9 @@ EXPORT_SYMBOL(tcp_create_openreq_child); * validation and inside tcp_v4_reqsk_send_ack(). Can we do better? * * We don't need to initialize tmp_opt.sack_ok as we don't use the results + * + * Note: If @fastopen is true, this can be called from process context. + * Otherwise, this is from BH context. */
struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb, @@ -717,7 +720,7 @@ struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb, &tcp_rsk(req)->last_oow_ack_time)) req->rsk_ops->send_ack(sk, skb, req); if (paws_reject) - __NET_INC_STATS(sock_net(sk), LINUX_MIB_PAWSESTABREJECTED); + NET_INC_STATS(sock_net(sk), LINUX_MIB_PAWSESTABREJECTED); return NULL; }
@@ -736,7 +739,7 @@ struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb, * "fourth, check the SYN bit" */ if (flg & (TCP_FLAG_RST|TCP_FLAG_SYN)) { - __TCP_INC_STATS(sock_net(sk), TCP_MIB_ATTEMPTFAILS); + TCP_INC_STATS(sock_net(sk), TCP_MIB_ATTEMPTFAILS); goto embryonic_reset; }