6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit a54d51fb2dfb846aedf3751af501e9688db447f5 ]
Generic sk_busy_loop_end() only looks at sk->sk_receive_queue
for presence of packets.
Problem is that for UDP sockets after blamed commit, some packets
could be present in another queue: udp_sk(sk)->reader_queue
In some cases, a busy poller could spin until timeout expiration,
even if some packets are available in udp_sk(sk)->reader_queue.
v3: - make sk_busy_loop_end() nicer (Willem)
v2: - add a READ_ONCE(sk->sk_family) in sk_is_inet() to avoid KCSAN splats.
- add a sk_is_inet() check in sk_is_udp() (Willem feedback)
- add a sk_is_inet() check in sk_is_tcp().
Fixes: 2276f58ac589 ("udp: use a separate rx queue for packet reception")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reviewed-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Reviewed-by: Willem de Bruijn <willemb@xxxxxxxxxx>
Reviewed-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
include/linux/skmsg.h | 6 ------
include/net/inet_sock.h | 5 -----
include/net/sock.h | 18 +++++++++++++++++-
net/core/sock.c | 11 +++++++++--
4 files changed, 26 insertions(+), 14 deletions(-)
diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index c953b8c0d2f4..bd4418377bac 100644
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h
@@ -500,12 +500,6 @@ static inline bool sk_psock_strp_enabled(struct sk_psock *psock)
return !!psock->saved_data_ready;
}
-static inline bool sk_is_udp(const struct sock *sk)
-{
- return sk->sk_type == SOCK_DGRAM &&
- sk->sk_protocol == IPPROTO_UDP;
-}
-
#if IS_ENABLED(CONFIG_NET_SOCK_MSG)
#define BPF_F_STRPARSER (1UL << 1)
diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index c2432c2addc8..c98890e21401 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -270,11 +270,6 @@ struct inet_sock {
#define IP_CMSG_CHECKSUM BIT(7)
#define IP_CMSG_RECVFRAGSIZE BIT(8)
-static inline bool sk_is_inet(struct sock *sk)
-{
- return sk->sk_family == AF_INET || sk->sk_family == AF_INET6;
-}
-
/**
* sk_to_full_sk - Access to a full socket
* @sk: pointer to a socket
diff --git a/include/net/sock.h b/include/net/sock.h
index 6b51e85ae69e..579732d47dfc 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2824,9 +2824,25 @@ static inline void skb_setup_tx_timestamp(struct sk_buff *skb, __u16 tsflags)
&skb_shinfo(skb)->tskey);
}
+static inline bool sk_is_inet(const struct sock *sk)
+{
+ int family = READ_ONCE(sk->sk_family);
+
+ return family == AF_INET || family == AF_INET6;
+}
+
static inline bool sk_is_tcp(const struct sock *sk)
{
- return sk->sk_type == SOCK_STREAM && sk->sk_protocol == IPPROTO_TCP;
+ return sk_is_inet(sk) &&
+ sk->sk_type == SOCK_STREAM &&
+ sk->sk_protocol == IPPROTO_TCP;
+}
+
+static inline bool sk_is_udp(const struct sock *sk)
+{
+ return sk_is_inet(sk) &&
+ sk->sk_type == SOCK_DGRAM &&
+ sk->sk_protocol == IPPROTO_UDP;
}
static inline bool sk_is_stream_unix(const struct sock *sk)
diff --git a/net/core/sock.c b/net/core/sock.c
index c50a14a02edd..c8803b95ea0d 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -107,6 +107,7 @@
#include <linux/interrupt.h>
#include <linux/poll.h>
#include <linux/tcp.h>
+#include <linux/udp.h>
#include <linux/init.h>
#include <linux/highmem.h>
#include <linux/user_namespace.h>
@@ -4109,8 +4110,14 @@ bool sk_busy_loop_end(void *p, unsigned long start_time)
{
struct sock *sk = p;
- return !skb_queue_empty_lockless(&sk->sk_receive_queue) ||
- sk_busy_loop_timeout(sk, start_time);
+ if (!skb_queue_empty_lockless(&sk->sk_receive_queue))
+ return true;
+
+ if (sk_is_udp(sk) &&
+ !skb_queue_empty_lockless(&udp_sk(sk)->reader_queue))
+ return true;
+
+ return sk_busy_loop_timeout(sk, start_time);
}
EXPORT_SYMBOL(sk_busy_loop_end);
#endif /* CONFIG_NET_RX_BUSY_POLL */
--
2.43.0
