Re: [PATCH net v1 1/3] net: core: propagate unreadable flag in skb_zerocopy

From: Mina Almasry

Date: Mon Aug 03 2026 - 11:51:27 EST


On Sun, Aug 2, 2026 at 5:33 AM Pavel Begunkov <asml.silence@xxxxxxxxx> wrote:
>
> On 8/1/26 13:52, Mina Almasry wrote:
> > When skb_zerocopy() copies devmem payload fragments, it fails to update
> > the target skb's unreadable flag. This causes the target to appear as
> > readable memory.
> >
> > Propagate the unreadable flag if any devmem fragments were copied from
> > the source.
>
> From a quick look, it doesn't seem like the function would work reliably
> with netmems even with this patch, but that's a different kind of issue
> we can return to later. Curious, did you hit this in prod?
>

No, this is sashiko report on another patch.

I think you may be right about the need for another check. I'll double
check and if this partial fix doesn't get merged as-is i'll submit a
v2. Thanks!

--
Thanks,
Mina