Re: [PATCH v2 0/2] tcp: exclude old ACKs from fast path

[Eric Dumazet]

On Tue, Sep 8, 2026 at 12:38 PM Inbal Schussheim
<inbal.lipshtat@xxxxxxxxxxxxxxx> wrote:
>
> Exclude ACKs outside [SND.UNA, SND.NXT] from TCP header prediction so
> that they fall through to the slow path, where ACK
> validation is applied.
>
> Add a packetdrill test for a data segment carrying an
> excessively old ACK. The test fails on the unpatched kernel and passes
> with the fix.
>
> Changes in v2:
>
> - Exclude all ACKs before SND.UNA from header prediction instead of
>   duplicating old-ACK validation in the fast path.
> - Cover pure ACKs as well as data-carrying segments.
> - Let the existing slow path handle validation and challenge ACKs.
> - Remove the packetdrill reproducer from the commit message; add the
>   packetdrill test separately.

OK but you forgot to CC netdev@xxxxxxxxxxxxxxx and you forgot to tell
which tree you target.

Patches need to be sent to netdev@ (instead of lkml@) so that our CI
can run tests on them.

Please read Documentation/process/maintainer-netdev.rst for details.

Thanks.