Re: [PATCH net 1/1] ip6_tunnel: use skb_cow_head() in ip6_tnl_xmit()
From: Ido Schimmel <idosch@nvidia.com>
Date: 2026-08-09 07:58:08
On Fri, Aug 07, 2026 at 10:31:29AM +0200, Paolo Abeni wrote:
My my concern is against possible regressions. At this late stage of the release cycle we want to avoid them, even if there are already similar pre-existing bugs. AFAICS pktgen sets the per pkt_gen device F_SHARED flag unconditionally and push shared skbs when F_SHARED is set regardless the NIC priv_flags. What about addressing both issues in the same series? Something like the following (completely untested) would do:
I don't have time to look into pktgen right now. I disagree with conditioning the merging of this fix - which makes IPv6 tunnels consistent with existing ones - on fixing a benchmarking / testing module that is not available to unprivileged users.
quoted hunk ↗ jump to hunk
---diff --git a/net/core/pktgen.c b/net/core/pktgen.c index ee64f3012321..a7126d639586 100644 --- a/net/core/pktgen.c +++ b/net/core/pktgen.c@@ -1385,6 +1385,9 @@ static ssize_t pktgen_if_write(struct file *file, return -EINVAL; pkt_dev->flags &= ~flag; } else { + if (!(pkt_dev->odev->priv_flags & + IFF_TX_SKB_SHARING)) + return -EINVAL; pkt_dev->flags |= flag;
Doesn't this reject the enablement of any flag (not just "SHARED") on a device that doesn't advertise IFF_TX_SKB_SHARING?
quoted hunk ↗ jump to hunk
}@@ -3868,13 +3871,15 @@ static int pktgen_add_device(struct pktgen_thread *t, const char *ifname) pkt_dev->svlan_id = 0xffff; pkt_dev->burst = 1; pkt_dev->node = NUMA_NO_NODE; - pkt_dev->flags = F_SHARED; /* SKB shared by default */ + pkt_dev->flags = 0; err = pktgen_setup_dev(t->net, pkt_dev, ifname); if (err) goto out1; - if (pkt_dev->odev->priv_flags & IFF_TX_SKB_SHARING) + if (pkt_dev->odev->priv_flags & IFF_TX_SKB_SHARING) { pkt_dev->clone_skb = pg_clone_skb_d; + pkt_dev->flags |= F_SHARED; + } pkt_dev->entry = proc_create_data(ifname, 0600, t->net->proc_dir, &pktgen_if_proc_ops, pkt_dev); ---/P