linux-kernel - Re: [PATCH v2] KVM: x86: degrade WARN to pr_warn

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Date:   Wed, 26 Jun 2019 14:24:10 +0200
From:   Alexander Potapenko <glider@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     LKML <linux-kernel@...r.kernel.org>, kvm@...r.kernel.org
Subject: Re: [PATCH v2] KVM: x86: degrade WARN to pr_warn_ratelimited

On Wed, Jun 26, 2019 at 2:19 PM Paolo Bonzini <pbonzini@...hat.com> wrote:
>
> This warning can be triggered easily by userspace, so it should certainly not
> cause a panic if panic_on_warn is set.
>
Can you please also add the Reported-by tag here?

Reported-by: syzbot+c03f30b4f4c46bdf8575@...kaller.appspotmail.com
> Suggested-by: Alexander Potapenko <glider@...gle.com>
> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Acked-by: Alexander Potapenko <glider@...gle.com>
> ---
>  arch/x86/kvm/x86.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 83aefd759846..66585cf42d7f 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -1557,7 +1557,7 @@ static int set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz, bool scale)
>                         vcpu->arch.tsc_always_catchup = 1;
>                         return 0;
>                 } else {
> -                       WARN(1, "user requested TSC rate below hardware speed\n");
> +                       pr_warn_ratelimited("user requested TSC rate below hardware speed\n");
>                         return -1;
>                 }
>         }
> @@ -1567,8 +1567,8 @@ static int set_tsc_khz(struct kvm_vcpu *vcpu, u32 user_tsc_khz, bool scale)
>                                 user_tsc_khz, tsc_khz);
>
>         if (ratio == 0 || ratio >= kvm_max_tsc_scaling_ratio) {
> -               WARN_ONCE(1, "Invalid TSC scaling ratio - virtual-tsc-khz=%u\n",
> -                         user_tsc_khz);
> +               pr_warn_ratelimited("Invalid TSC scaling ratio - virtual-tsc-khz=%u\n",
> +                                   user_tsc_khz);
>                 return -1;
>         }
>
> --
> 1.8.3.1
>


-- 
Alexander Potapenko
Software Engineer

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