Re: [PATCH net v2] idpf: handle NULL adev in idpf_idc_vdev_mtu_event

From: Simon Horman

Date: Wed May 20 2026 - 17:35:56 EST


On Tue, May 19, 2026 at 09:19:23PM +0100, David CARLIER wrote:
> > This is an AI-generated review of your patch. The human sending this
> > email has considered the AI review valid, or at least plausible.
>
> Thanks for relaying this, Simon.
>
> The scenario this patch fixes is sequential, not concurrent:
> idpf_idc_vport_dev_ctrl(adapter, false) has already returned and
> vdev_info->adev is NULL by the time ndo_change_mtu reaches
> idpf_idc_vdev_mtu_event(). The original code dereferenced
> vdev_info->adev in device_lock() before the NULL check and oopses
> deterministically; READ_ONCE() + early-return resolves that.
>
> A truly concurrent idpf_idc_vport_dev_ctrl(_, false) racing an
> in-flight MTU event is a separate, pre-existing window: the original
> code took no reference between reading vdev_info->adev and
> dereferencing it either, so this patch neither introduces nor widens
> it. I haven't constructed a concrete interleaving against auxiliary-bus
> teardown and have no report of it triggering.
>
> Happy to post a follow-up bracketing the handler with
> get_device()/put_device() if you'd prefer, but I'd rather keep this
> one scoped to the Fixes: target.

Hi David,

Thanks for the clarification.
I agree we can treat concurrency as a separate issue.