Re: [PATCH net] selftests: drv-net: ping: Wait for carrier after toggling offloads

From: Jakub Kicinski

Date: Wed Mar 18 2026 - 20:28:20 EST


On Tue, 17 Mar 2026 18:01:17 -0700 Pin-yen Lin wrote:
> Toggling checksum offload (or HW-GRO via feature dependencies) can cause
> certain physical interfaces to undergo a reset or a temporary link-down
> state. In the ping.py test, this leads to immediate test failures if the
> ping is attempted before the carrier is restored.
>
> This is observed when running the test with GVE driver when HW-GRO is
> enabled. When checksum offload is toggled, HW-GRO is toggled as well
> because of the feature dependency. This leads to an interface reset,
> causing the subsequent ping to fail.
>
> Add a sleep period after changing these features to allow the link to
> stabilize.

Sounds like the test found a legitimate problem. The configuration
should not return to user space until the operation has completed.
User should not have to sleep 10sec each time they touch NIC
configuration.
--
pw-bot: reject