Messages in this thread Patch in this message | | | Date | Fri, 24 Mar 2023 10:06:21 +0100 | From | Stefano Garzarella <> | Subject | Re: [syzbot] [kvm?] [net?] [virt?] general protection fault in virtio_transport_purge_skbs |
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On Fri, Mar 24, 2023 at 9:55 AM Stefano Garzarella <sgarzare@redhat.com> wrote: > > On Fri, Mar 24, 2023 at 9:31 AM Stefano Garzarella <sgarzare@redhat.com> wrote: > > > > Hi Bobby, > > can you take a look at this report? > > > > It seems related to the changes we made to support skbuff. > > Could it be a problem of concurrent access to pkt_queue ? > > IIUC we should hold pkt_queue.lock when we call skb_queue_splice_init() > and remove pkt_list_lock. (or hold pkt_list_lock when calling > virtio_transport_purge_skbs, but pkt_list_lock seems useless now that > we use skbuff) >
In the previous patch was missing a hunk, new one attached:
#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git fff5a5e7f528
--- a/net/vmw_vsock/vsock_loopback.c +++ b/net/vmw_vsock/vsock_loopback.c @@ -15,7 +15,6 @@ struct vsock_loopback { struct workqueue_struct *workqueue;
- spinlock_t pkt_list_lock; /* protects pkt_list */ struct sk_buff_head pkt_queue; struct work_struct pkt_work; }; @@ -32,9 +31,7 @@ static int vsock_loopback_send_pkt(struct sk_buff *skb) struct vsock_loopback *vsock = &the_vsock_loopback; int len = skb->len;
- spin_lock_bh(&vsock->pkt_list_lock); skb_queue_tail(&vsock->pkt_queue, skb); - spin_unlock_bh(&vsock->pkt_list_lock);
queue_work(vsock->workqueue, &vsock->pkt_work);
@@ -113,9 +110,9 @@ static void vsock_loopback_work(struct work_struct *work)
skb_queue_head_init(&pkts);
- spin_lock_bh(&vsock->pkt_list_lock); + spin_lock_bh(&vsock->pkt_queue.lock); skb_queue_splice_init(&vsock->pkt_queue, &pkts); - spin_unlock_bh(&vsock->pkt_list_lock); + spin_unlock_bh(&vsock->pkt_queue.lock);
while ((skb = __skb_dequeue(&pkts))) { virtio_transport_deliver_tap_pkt(skb); @@ -132,7 +129,6 @@ static int __init vsock_loopback_init(void) if (!vsock->workqueue) return -ENOMEM;
- spin_lock_init(&vsock->pkt_list_lock); skb_queue_head_init(&vsock->pkt_queue); INIT_WORK(&vsock->pkt_work, vsock_loopback_work);
@@ -156,9 +152,7 @@ static void __exit vsock_loopback_exit(void)
flush_work(&vsock->pkt_work);
- spin_lock_bh(&vsock->pkt_list_lock); virtio_vsock_skb_queue_purge(&vsock->pkt_queue); - spin_unlock_bh(&vsock->pkt_list_lock);
destroy_workqueue(vsock->workqueue); }
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