This is a note to let you know that I've just added the patch titled
net: annotate lockless accesses to sk->sk_ack_backlog
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-annotate-lockless-accesses-to-sk-sk_ack_backlog.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 88e8ad29aece33e46f2063d0b39479922cce2434
Author: Eric Dumazet <edumazet@xxxxxxxxxx>
Date: Tue Nov 5 14:11:53 2019 -0800
net: annotate lockless accesses to sk->sk_ack_backlog
[ Upstream commit 288efe8606b62d0753ba6722b36ef241877251fd ]
sk->sk_ack_backlog can be read without any lock being held.
We need to use READ_ONCE()/WRITE_ONCE() to avoid load/store tearing
and/or potential KCSAN warnings.
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Stable-dep-of: 4d5c70e6155d ("sctp: ensure sk_state is set to CLOSED if hashing fails in sctp_listen_start")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/net/sock.h b/include/net/sock.h
index 250d5a6c508cb..c0d5775bc62c0 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -873,17 +873,17 @@ static inline gfp_t sk_gfp_mask(const struct sock *sk, gfp_t gfp_mask)
static inline void sk_acceptq_removed(struct sock *sk)
{
- sk->sk_ack_backlog--;
+ WRITE_ONCE(sk->sk_ack_backlog, sk->sk_ack_backlog - 1);
}
static inline void sk_acceptq_added(struct sock *sk)
{
- sk->sk_ack_backlog++;
+ WRITE_ONCE(sk->sk_ack_backlog, sk->sk_ack_backlog + 1);
}
static inline bool sk_acceptq_is_full(const struct sock *sk)
{
- return sk->sk_ack_backlog > sk->sk_max_ack_backlog;
+ return READ_ONCE(sk->sk_ack_backlog) > sk->sk_max_ack_backlog;
}
/*
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 54399256a4380..4800422169f95 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3280,7 +3280,7 @@ void tcp_get_info(struct sock *sk, struct tcp_info *info)
* tcpi_unacked -> Number of children ready for accept()
* tcpi_sacked -> max backlog
*/
- info->tcpi_unacked = sk->sk_ack_backlog;
+ info->tcpi_unacked = READ_ONCE(sk->sk_ack_backlog);
info->tcpi_sacked = sk->sk_max_ack_backlog;
return;
}
diff --git a/net/ipv4/tcp_diag.c b/net/ipv4/tcp_diag.c
index 549506162ddec..edfbab54c46f4 100644
--- a/net/ipv4/tcp_diag.c
+++ b/net/ipv4/tcp_diag.c
@@ -21,7 +21,7 @@ static void tcp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
struct tcp_info *info = _info;
if (inet_sk_state_load(sk) == TCP_LISTEN) {
- r->idiag_rqueue = sk->sk_ack_backlog;
+ r->idiag_rqueue = READ_ONCE(sk->sk_ack_backlog);
r->idiag_wqueue = sk->sk_max_ack_backlog;
} else if (sk->sk_type == SOCK_STREAM) {
const struct tcp_sock *tp = tcp_sk(sk);
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index a0a4dbcf8c12f..1f8a9b323a0dd 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2500,7 +2500,7 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
state = inet_sk_state_load(sk);
if (state == TCP_LISTEN)
- rx_queue = sk->sk_ack_backlog;
+ rx_queue = READ_ONCE(sk->sk_ack_backlog);
else
/* Because we don't lock the socket,
* we might find a transient negative value.
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 81b7ef21180bf..8be41d6c4278b 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1921,7 +1921,7 @@ static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
state = inet_sk_state_load(sp);
if (state == TCP_LISTEN)
- rx_queue = sp->sk_ack_backlog;
+ rx_queue = READ_ONCE(sp->sk_ack_backlog);
else
/* Because we don't lock the socket,
* we might find a transient negative value.
diff --git a/net/sched/em_meta.c b/net/sched/em_meta.c
index ad007cdcec978..c4c297627feac 100644
--- a/net/sched/em_meta.c
+++ b/net/sched/em_meta.c
@@ -521,7 +521,7 @@ META_COLLECTOR(int_sk_ack_bl)
*err = -1;
return;
}
- dst->value = sk->sk_ack_backlog;
+ dst->value = READ_ONCE(sk->sk_ack_backlog);
}
META_COLLECTOR(int_sk_max_ack_bl)
diff --git a/net/sctp/diag.c b/net/sctp/diag.c
index 2d0318a7352c2..e0785592fdd63 100644
--- a/net/sctp/diag.c
+++ b/net/sctp/diag.c
@@ -416,7 +416,7 @@ static void sctp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
r->idiag_rqueue = atomic_read(&infox->asoc->rmem_alloc);
r->idiag_wqueue = infox->asoc->sndbuf_used;
} else {
- r->idiag_rqueue = sk->sk_ack_backlog;
+ r->idiag_rqueue = READ_ONCE(sk->sk_ack_backlog);
r->idiag_wqueue = sk->sk_max_ack_backlog;
}
if (infox->sctpinfo)
