Re: [PATCH] KVM: x86: remove bogus user-triggerable WARN_ON

From: Thomas Gleixner
Date: Fri Mar 20 2020 - 11:23:34 EST


Thomas Gleixner <tglx@xxxxxxxxxxxxx> writes:

> Paolo Bonzini <pbonzini@xxxxxxxxxx> writes:
>> The WARN_ON is essentially comparing a user-provided value with 0. It is
>> trivial to trigger it just by passing garbage to KVM_SET_CLOCK. Guests
>> can break if you do so, but if it hurts when you do like this just do not
>> do it.
>
> Yes, it's a user provided value and it's completely unchecked. If that
> value is bogus then the guest will go sideways because timekeeping is
> completely busted. At least you should explain WHY you don't care.

Or why it does not matter....