From: Eric Dumazet <edumazet@google.com>
Date: Mon, 27 Feb 2023 08:33:36 +0000
Subject: [PATCH] tcp: tcp_check_req() can be called from process context
References: bsc#1012628
Patch-mainline: 6.2.5
Git-commit: 580f98cc33a260bb8c6a39ae2921b29586b84fdf
[ 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@cloudflare.com/T/
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>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
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 e002f2e1..9a7ef773 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -597,6 +597,9 @@ 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,
@@ -748,7 +751,7 @@ 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;
}
@@ -767,7 +770,7 @@ 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;
}
--
2.35.3