On Fri, 28 Nov 2025 21:35:57 +0800 Edward Adam Davis wrote: > In zerocopy_fill_skb_from_iter(), if two copy operations are performed > and the first one succeeds while the second one fails, it returns a > failure but the count in iterator has already been decremented due to > the first successful copy. This ultimately affects the local variable > rest_len in virtio_transport_send_pkt_info(), causing the remaining > count in rest_len to be greater than the actual iterator count. As a > result, packet sending operations continue even when the iterator count > is zero, which further leads to skb->len being 0 and triggers the warning > reported by syzbot [1].
Please follow the subsystem guidelines for posting patches: https://www.kernel.org/doc/html/next/process/maintainer-netdev.html Your patch breaks zerocopy tests.
