Re: [PATCH v4 08/18] mshv: Fix level-triggered check on uninitialized data

From: Anirudh Rayabharam

Date: Wed May 13 2026 - 08:19:51 EST


On Thu, May 07, 2026 at 03:43:43PM +0000, Stanislav Kinsburskii wrote:
> In mshv_irqfd_assign(), the level-triggered validation for resample
> irqfds checks irqfd_lapic_irq.lapic_control.level_triggered before
> mshv_irqfd_update() has populated the field. Since the irqfd struct is
> zero-allocated, level_triggered is always 0 at that point, causing the
> check to always reject resample irqfds with -EINVAL. This makes
> level-triggered interrupt resampling — used to avoid interrupt storms
> with assigned devices — completely non-functional.

What bugs would this manifest as? Why haven't we seen any such bugs so
far?

Thanks,
Anirudh.