Re: [PATCH] net/sched: fq_pie: enforce memory_limit without wrapped accounting

[Eric Dumazet]

On Mon, Jun 8, 2026 at 5:41 PM Samuel Moelius
<sam.moelius@xxxxxxxxxxxxxxx> wrote:
>
> fq_pie checks memory usage by adding the next packet size to the current
> usage before comparing against memory_limit.  That addition can wrap and
> make an over-limit enqueue look acceptable.
>
> The scheduler can also fail to enforce memory_limit consistently across
> enqueue paths.
>
> Use overflow-safe accounting and reject packets that would exceed
> memory_limit.
>
> Assisted-by: Codex:gpt-5.5-cyber-preview
> Signed-off-by: Samuel Moelius <sam.moelius@xxxxxxxxxxxxxxx>
> ---

NACK