From: Michael S. Tsirkin Date: Wed, 2 Oct 2024 13:35:20 +0000 (-0400) Subject: vsock/virtio: use GFP_ATOMIC under RCU read lock X-Git-Tag: v6.12-rc3~33^2~1 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a194c985973276b2f280428c848f20369bb83734;p=thirdparty%2Flinux.git vsock/virtio: use GFP_ATOMIC under RCU read lock virtio_transport_send_pkt in now called on transport fast path, under RCU read lock. In that case, we have a bug: virtio_add_sgs is called with GFP_KERNEL, and might sleep. Pass the gfp flags as an argument, and use GFP_ATOMIC on the fast path. Link: https://lore.kernel.org/all/hfcr2aget2zojmqpr4uhlzvnep4vgskblx5b6xf2ddosbsrke7@nt34bxgp7j2x Fixes: efcd71af38be ("vsock/virtio: avoid queuing packets when intermediate queue is empty") Reported-by: Christian Brauner Cc: Stefano Garzarella Cc: Luigi Leonardi Message-ID: <3fbfb6e871f625f89eb578c7228e127437b1975a.1727876449.git.mst@redhat.com> Signed-off-by: Michael S. Tsirkin Reviewed-by: Pankaj Gupta Reviewed-by: Christian Brauner Reviewed-by: Luigi Leonardi Reviewed-by: Stefano Garzarella --- diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c index f992f9a216f05..0cd965f24609e 100644 --- a/net/vmw_vsock/virtio_transport.c +++ b/net/vmw_vsock/virtio_transport.c @@ -96,7 +96,7 @@ out_rcu: /* Caller need to hold vsock->tx_lock on vq */ static int virtio_transport_send_skb(struct sk_buff *skb, struct virtqueue *vq, - struct virtio_vsock *vsock) + struct virtio_vsock *vsock, gfp_t gfp) { int ret, in_sg = 0, out_sg = 0; struct scatterlist **sgs; @@ -140,7 +140,7 @@ static int virtio_transport_send_skb(struct sk_buff *skb, struct virtqueue *vq, } } - ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, skb, GFP_KERNEL); + ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, skb, gfp); /* Usually this means that there is no more space available in * the vq */ @@ -178,7 +178,7 @@ virtio_transport_send_pkt_work(struct work_struct *work) reply = virtio_vsock_skb_reply(skb); - ret = virtio_transport_send_skb(skb, vq, vsock); + ret = virtio_transport_send_skb(skb, vq, vsock, GFP_KERNEL); if (ret < 0) { virtio_vsock_skb_queue_head(&vsock->send_pkt_queue, skb); break; @@ -221,7 +221,7 @@ static int virtio_transport_send_skb_fast_path(struct virtio_vsock *vsock, struc if (unlikely(ret == 0)) return -EBUSY; - ret = virtio_transport_send_skb(skb, vq, vsock); + ret = virtio_transport_send_skb(skb, vq, vsock, GFP_ATOMIC); if (ret == 0) virtqueue_kick(vq);