netdev - Re: [PATCH 0/3] vhost_task: KVM: Fix a race where KVM wakes an exited task

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Message-ID: <CAPpAL=wp61suVw-VdqpT-Kxxztaokg_-DkjsVEHDTg7rxzsnbw@mail.gmail.com>
Date: Thu, 28 Aug 2025 10:19:03 +0800
From: Lei Yang <leiyang@...hat.com>
To: Sean Christopherson <seanjc@...gle.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>, "Michael S. Tsirkin" <mst@...hat.com>, 
	Jason Wang <jasowang@...hat.com>, kvm@...r.kernel.org, virtualization@...ts.linux.dev, 
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Subject: Re: [PATCH 0/3] vhost_task: KVM: Fix a race where KVM wakes an exited task

Tested this series of patches with vhost-net regression tests,
everything works fine.

Tested-by: Lei Yang <leiyang@...hat.com>

On Tue, Aug 26, 2025 at 8:40 AM Sean Christopherson <seanjc@...gle.com> wrote:
>
> Fix a bug where KVM attempts to wake a vhost task that has already exited in
> response to a fatal signal, and tack on a few cleanups to harden against
> introducing similar bugs in the future.
>
> Somehow, this only started causing problems when commit 56180dd20c19 ("futex:
> Use RCU-based per-CPU reference counting instead of rcuref_t") landed.  I have
> no idea why the futex changes exposed the bug, and I don't care all that much,
> as this is firmly a KVM bug.
>
> Sean Christopherson (3):
>   vhost_task: KVM: Don't wake KVM x86's recovery thread if vhost task
>     was killed
>   vhost_task: Allow caller to omit handle_sigkill() callback
>   KVM: x86/mmu: Don't register a sigkill callback for NX hugepage
>     recovery tasks
>
>  arch/x86/kvm/mmu/mmu.c           |  9 ++----
>  include/linux/sched/vhost_task.h |  1 +
>  kernel/vhost_task.c              | 52 +++++++++++++++++++++++++++++---
>  3 files changed, 51 insertions(+), 11 deletions(-)
>
>
> base-commit: 1b237f190eb3d36f52dffe07a40b5eb210280e00
> --
> 2.51.0.261.g7ce5a0a67e-goog
>
>