RE: [PATCH] mbuf: fix packet copy

Morten Brørup
2026-01-03T17:46:08Z

PING for review.

> From: Morten Brørup [mailto:mb@smartsharesystems.com]
> Sent: Wednesday, 19 November 2025 13.04
>
> Requests for copying the at the end of a packet incorrectly returned
> NULL,
> as if copying past the end of a packet.
>
> When allocating copies from a mempool using pinned external buffers,
> the
> external flag was not preserved in these mbufs.
>
> Fixes: c3a90c381daa ("mbuf: add a copy routine")
>
> Signed-off-by: Morten Brørup <mb@smartsharesystems.com>
> ---
> lib/mbuf/rte_mbuf.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/lib/mbuf/rte_mbuf.c b/lib/mbuf/rte_mbuf.c
> index 0d931c7a15..e639aff03e 100644
> --- a/lib/mbuf/rte_mbuf.c
> +++ b/lib/mbuf/rte_mbuf.c
> @@ -675,7 +675,7 @@ rte_pktmbuf_copy(const struct rte_mbuf *m, struct
> rte_mempool *mp,
> __rte_mbuf_sanity_check(m, 1);
>
> /* check for request to copy at offset past end of mbuf */
> - if (unlikely(off >= m->pkt_len))
> + if (unlikely(off > m->pkt_len))
> return NULL;
>
> mc = rte_pktmbuf_alloc(mp);
> @@ -688,8 +688,8 @@ rte_pktmbuf_copy(const struct rte_mbuf *m, struct
> rte_mempool *mp,
>
> __rte_pktmbuf_copy_hdr(mc, m);
>
> - /* copied mbuf is not indirect or external */
> - mc->ol_flags = m->ol_flags &
> ~(RTE_MBUF_F_INDIRECT|RTE_MBUF_F_EXTERNAL);
> + /* copy flags except indirect and external, and preserve flags of
> newly allocated mbuf */
> + mc->ol_flags |= m->ol_flags &
> ~(RTE_MBUF_F_INDIRECT|RTE_MBUF_F_EXTERNAL);
>
> prev = &mc->next;
> m_last = mc;
> --
> 2.43.0