From 41f9a1757ffc010cc3debaad9a56af8ad88d0c6d Mon Sep 17 00:00:00 2001 From: Yuan Wang Date: Fri, 17 Jun 2022 10:42:29 +0800 Subject: [PATCH] net/virtio-user: fix socket non-blocking mode The virtio-user initialization requires unix socket to receive backend messages in block mode. However, vhost_user_update_link_state() sets the same socket to nonblocking via fcntl, which affects all threads. Enabling the rxq interrupt can causes both of these behaviors to occur concurrently, with the result that the initialization may fail because no messages are received in nonblocking socket. Thread 1: virtio_init_device() --> virtio_user_start_device() --> vhost_user_set_memory_table() --> vhost_user_check_reply_ack() Thread 2: virtio_interrupt_handler() --> vhost_user_update_link_state() Fix that by replacing O_NONBLOCK with the recv per-call option MSG_DONTWAIT. Fixes: ef53b6030039 ("net/virtio-user: support LSC") Cc: stable@dpdk.org Signed-off-by: Yuan Wang Acked-by: Stephen Hemminger Reviewed-by: Chenbo Xia --- drivers/net/virtio/virtio_user/vhost_user.c | 15 +-------------- 1 file changed, 1 insertion(+), 14 deletions(-) diff --git a/drivers/net/virtio/virtio_user/vhost_user.c b/drivers/net/virtio/virtio_user/vhost_user.c index 7d1749114d..198bd63d3c 100644 --- a/drivers/net/virtio/virtio_user/vhost_user.c +++ b/drivers/net/virtio/virtio_user/vhost_user.c @@ -940,15 +940,8 @@ vhost_user_update_link_state(struct virtio_user_dev *dev) if (data->vhostfd >= 0) { int r; - int flags; - flags = fcntl(data->vhostfd, F_GETFL); - if (fcntl(data->vhostfd, F_SETFL, flags | O_NONBLOCK) == -1) { - PMD_DRV_LOG(ERR, "error setting O_NONBLOCK flag"); - return -1; - } - - r = recv(data->vhostfd, buf, 128, MSG_PEEK); + r = recv(data->vhostfd, buf, 128, MSG_PEEK | MSG_DONTWAIT); if (r == 0 || (r < 0 && errno != EAGAIN)) { dev->net_status &= (~VIRTIO_NET_S_LINK_UP); PMD_DRV_LOG(ERR, "virtio-user port %u is down", dev->hw.port_id); @@ -963,12 +956,6 @@ vhost_user_update_link_state(struct virtio_user_dev *dev) } else { dev->net_status |= VIRTIO_NET_S_LINK_UP; } - - if (fcntl(data->vhostfd, F_SETFL, - flags & ~O_NONBLOCK) == -1) { - PMD_DRV_LOG(ERR, "error clearing O_NONBLOCK flag"); - return -1; - } } else if (dev->is_server) { dev->net_status &= (~VIRTIO_NET_S_LINK_UP); if (virtio_user_dev_server_reconnect(dev) >= 0) -- 2.39.5