The xdp_convert_buff_to_frame() function can return NULL when there is insufficient headroom in the buffer to store the xdp_frame structure or when the driver didn't reserve enough tailroom for skb_shared_info. Currently, the sfc driver does not check for this NULL return value in the XDP_TX case within efx_do_xdp(). While the efx_xdp_tx_buffers() function has some defensive checks, passing a NULL xdpf can still lead to undefined behavior when the function tries to access xdpf->len and xdpf->data. Fix by adding a proper NULL check in the XDP_TX case, following the suggestions of the developers. Fixes: 1b698fa5d8ef ("xdp: Rename convert_to_xdp_frame in xdp_convert_buff_to_frame") Signed-off-by: Chenyuan Yang Cc: Kunwu Chan Cc: Edward Cree --- drivers/net/ethernet/sfc/rx.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/sfc/rx.c b/drivers/net/ethernet/sfc/rx.c index ffca82207e47..b56457c23f66 100644 --- a/drivers/net/ethernet/sfc/rx.c +++ b/drivers/net/ethernet/sfc/rx.c @@ -308,14 +308,20 @@ static bool efx_do_xdp(struct efx_nic *efx, struct efx_channel *channel, case XDP_TX: /* Buffer ownership passes to tx on success. */ xdpf = xdp_convert_buff_to_frame(&xdp); - err = efx_xdp_tx_buffers(efx, 1, &xdpf, true); + if (unlikely(!xdpf)) + err = -ENOBUFS; + else + err = efx_xdp_tx_buffers(efx, 1, &xdpf, true); + if (unlikely(err != 1)) { efx_free_rx_buffers(rx_queue, rx_buf, 1); if (net_ratelimit()) netif_err(efx, rx_err, efx->net_dev, - "XDP TX failed (%d)\n", err); + "XDP TX failed (%d)%s\n", err, + err == -ENOBUFS ? " [frame conversion]" : ""); channel->n_rx_xdp_bad_drops++; - trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act); + if (err != -ENOBUFS) + trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act); } else { channel->n_rx_xdp_tx++; } -- 2.34.1