Re: [PATCH net v3 1/2] net: core: propagate unreadable flag in skb_zerocopy
From: Ilya Maximets <i.maximets@ovn.org>
Date: 2026-08-12 15:52:16
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On 8/11/26 9:53 PM, Mina Almasry wrote:
quoted hunk ↗ jump to hunk
diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c index ae69b2cabab9e..482893a5f67dc 100644 --- a/net/openvswitch/datapath.c +++ b/net/openvswitch/datapath.c@@ -467,6 +467,9 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb, if (!dp_ifindex) return -ENODEV; + if (!skb_frags_readable(skb)) + return -EFAULT; + if (skb_vlan_tag_present(skb)) { nskb = skb_clone(skb, GFP_ATOMIC); if (!nskb)
FWIW, the devmem integration doesn't seem well-designed. I understand that it is for performance, but IMO there should be a way to copy the data on a slow path to avoid dropping the packets. Clamping without notifying the users that the packet is truncated is not a good solution. Not for OVS, not for other parts of the kernel networking stack. It's a uAPI breakage. As it is, there is not much we can do here without extensive changes in userspace applications, so for this OVS block: Reviewed-by: Ilya Maximets <i.maximets@ovn.org>