From: Eric Dumazet edumazet@google.com
[ Upstream commit 60b173ca3d1cd1782bd0096dc17298ec242f6fb1 ]
reqsk_queue_empty() is called from inet_csk_listen_poll() while other cpus might write ->rskq_accept_head value.
Use {READ|WRITE}_ONCE() to avoid compiler tricks and potential KCSAN splats.
Fixes: fff1f3001cc5 ("tcp: add a spinlock to protect struct request_sock_queue") Signed-off-by: Eric Dumazet edumazet@google.com Signed-off-by: Jakub Kicinski jakub.kicinski@netronome.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/xen/pvcalls-back.c | 2 +- include/net/request_sock.h | 4 ++-- net/ipv4/inet_connection_sock.c | 2 +- 3 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c index abd6dbc29ac28..58be15c27b6d6 100644 --- a/drivers/xen/pvcalls-back.c +++ b/drivers/xen/pvcalls-back.c @@ -792,7 +792,7 @@ static int pvcalls_back_poll(struct xenbus_device *dev, mappass->reqcopy = *req; icsk = inet_csk(mappass->sock->sk); queue = &icsk->icsk_accept_queue; - data = queue->rskq_accept_head != NULL; + data = READ_ONCE(queue->rskq_accept_head) != NULL; if (data) { mappass->reqcopy.cmd = 0; ret = 0; diff --git a/include/net/request_sock.h b/include/net/request_sock.h index 23e22054aa60d..04aa2c7d35c4e 100644 --- a/include/net/request_sock.h +++ b/include/net/request_sock.h @@ -181,7 +181,7 @@ void reqsk_fastopen_remove(struct sock *sk, struct request_sock *req,
static inline bool reqsk_queue_empty(const struct request_sock_queue *queue) { - return queue->rskq_accept_head == NULL; + return READ_ONCE(queue->rskq_accept_head) == NULL; }
static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue, @@ -193,7 +193,7 @@ static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue req = queue->rskq_accept_head; if (req) { sk_acceptq_removed(parent); - queue->rskq_accept_head = req->dl_next; + WRITE_ONCE(queue->rskq_accept_head, req->dl_next); if (queue->rskq_accept_head == NULL) queue->rskq_accept_tail = NULL; } diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c index f7224c4fc30fe..da55ce62fe50b 100644 --- a/net/ipv4/inet_connection_sock.c +++ b/net/ipv4/inet_connection_sock.c @@ -936,7 +936,7 @@ struct sock *inet_csk_reqsk_queue_add(struct sock *sk, req->sk = child; req->dl_next = NULL; if (queue->rskq_accept_head == NULL) - queue->rskq_accept_head = req; + WRITE_ONCE(queue->rskq_accept_head, req); else queue->rskq_accept_tail->dl_next = req; queue->rskq_accept_tail = req;