# Re: \[PATCH net v3 0/6\] net: sched: fix quantum/mtu overflow in fq, fq\_codel, sch\_codel, fq\_pie, hhf, sfq

- From: patchwork-bot+netdevbpf@kernel.org
- Date: 2026-08-25 11:31:08 
- List: netdev
- Page: https://ratatoskr.run/netdev/2026/08/17458538
- Thread: https://ratatoskr.run/netdev/2026/08/17448949/t.md

```text
Hello:

This series was applied to netdev/net.git (main)
by Paolo Abeni [ref]:

On Sat, 22 Aug 2026 15:55:03 -0400 you wrote:
> Several qdiscs derive their per-flow quantum or CoDel mtu from
> psched_mtu() without an overflow or zero clamp, which can drive the
> dequeue/credit-refill loop into a soft lockup or silently disable the
> AQM. vega@nebusec.ai provided reports and PoCs for the following qdiscs:
> sch_fq, sch_fq_codel, sch_fq_pie, sch_hhf, and sch_sfq.
> 
> sch_codel was found by inspection for the same pattern. It's TheLinuxWay
> (i.e cutnpaste code from somewhere for your new feature) and the AIs
> are having a lot of fun finding patterns. We must overcome!
> 
> [...]

Here is the summary with links:
  - [net,v3,1/6] net/sched: fq: add overflow bounds to quantum and initial quantum
    https://git.kernel.org/netdev/net/c/709f34f7c28d
  - [net,v3,2/6] net/sched: fq_codel: clamp default quantum and mtu
    https://git.kernel.org/netdev/net/c/d9ebd8f9aa8b
  - [net,v3,3/6] net/sched: sch_codel: clamp default mtu to avoid disabling CoDel
    https://git.kernel.org/netdev/net/c/6439461f1618
  - [net,v3,4/6] net/sched: fq_pie: clamp default quantum to avoid signed overflow
    https://git.kernel.org/netdev/net/c/c86cd7ed0b0e
  - [net,v3,5/6] net/sched: hhf: clamp quantum before hhf_change() to avoid overflow
    https://git.kernel.org/netdev/net/c/2164b512b97b
  - [net,v3,6/6] net/sched: sfq: clamp quantum to avoid signed overflow soft lockup
    https://git.kernel.org/netdev/net/c/816e90057ab1

You are awesome, thank you!
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