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From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Sean Christopherson <seanjc@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	kvm@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
	Venkatesh Srinivas <venkateshs@google.com>,
	Lai Jiangshan <jiangshanlai+lkml@gmail.com>
Subject: Re: [PATCH 2/2] KVM: Guard cpusmask NULL check with CONFIG_CPUMASK_OFFSTACK
Date: Thu, 26 Aug 2021 12:24:06 +0200	[thread overview]
Message-ID: <878s0ojygp.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <YSa8z5vQKbFuLtew@google.com>

Sean Christopherson <seanjc@google.com> writes:

> On Wed, Aug 25, 2021, Lai Jiangshan wrote:
>> On Sat, Aug 21, 2021 at 8:09 AM Sean Christopherson <seanjc@google.com> wrote:
>> > @@ -277,6 +277,14 @@ bool kvm_make_vcpus_request_mask(struct kvm *kvm, unsigned int req,
>> >                 if (!(req & KVM_REQUEST_NO_WAKEUP) && kvm_vcpu_wake_up(vcpu))
>> >                         continue;
>> >
>> > +               /*
>> > +                * tmp can be NULL if cpumasks are allocated off stack, as
>> > +                * allocation of the mask is deliberately not fatal and is
>> > +                * handled by falling back to kicking all online CPUs.
>> > +                */
>> > +               if (IS_ENABLED(CONFIG_CPUMASK_OFFSTACK) && !tmp)
>> > +                       continue;
>> > +
>> 
>> Hello, Sean
>> 
>> I don't think it is a good idea to reinvent the cpumask_available().
>
> Using cpumask_available() is waaaay better, thanks!
>
> Vitaly / Paolo, take this one instead?
>

Sure, putting this to my v3, thanks!

-- 
Vitaly


      reply	other threads:[~2021-08-26 10:24 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-21  0:04 [PATCH 0/2] VM: Fix a benign race in kicking vCPUs Sean Christopherson
2021-08-21  0:05 ` [PATCH 1/2] KVM: Clean up benign vcpu->cpu data races when " Sean Christopherson
2021-08-23  7:49   ` Vitaly Kuznetsov
2021-08-21  0:05 ` [PATCH 2/2] KVM: Guard cpusmask NULL check with CONFIG_CPUMASK_OFFSTACK Sean Christopherson
2021-08-23  7:54   ` Vitaly Kuznetsov
2021-08-25  4:05   ` Lai Jiangshan
2021-08-25 21:57     ` Sean Christopherson
2021-08-26 10:24       ` Vitaly Kuznetsov [this message]

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