Forwarded: Re: [syzbot] [kvm?] [net?] [virt?] WARNING in virtio_transport_send_pkt_info

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Subject: Re: [syzbot] [kvm?] [net?] [virt?] WARNING in virtio_transport_send_pkt_info
Author: mst@xxxxxxxxxx


#syz test: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master


diff --git a/net/core/datagram.c b/net/core/datagram.c
index 94cc4705e91d..3b5695ad3714 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -686,6 +686,11 @@ int zerocopy_fill_skb_from_iter(struct sk_buff *skb,
 		if (refs)
 			page_ref_sub(last_head, refs);
 	}
+
+	/* Fail if we couldn't get all requested data, like linear copy does */
+	if (length > 0)
+		return -EFAULT;
+
 	return 0;
 }