Re: [PATCH] KVM: nVMX: Replace a BUG_ON(1) with BUG() to squash clang warning

From: Paolo Bonzini
Date: Mon May 04 2020 - 11:59:21 EST


On 04/05/20 17:35, Sean Christopherson wrote:
> Use BUG() in the impossible-to-hit default case when switching on the
> scope of INVEPT to squash a warning with clang 11 due to clang treating
> the BUG_ON() as conditional.
>
> >> arch/x86/kvm/vmx/nested.c:5246:3: warning: variable 'roots_to_free'
> is used uninitialized whenever 'if' condition is false
> [-Wsometimes-uninitialized]
> BUG_ON(1);
>
> Reported-by: kbuild test robot <lkp@xxxxxxxxx>
> Fixes: ce8fe7b77bd8 ("KVM: nVMX: Free only the affected contexts when emulating INVEPT")
> Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
> ---
> arch/x86/kvm/vmx/nested.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index 2c36f3f53108..669445136144 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -5249,7 +5249,7 @@ static int handle_invept(struct kvm_vcpu *vcpu)
> roots_to_free = KVM_MMU_ROOTS_ALL;
> break;
> default:
> - BUG_ON(1);
> + BUG();
> break;
> }
>
>

Queued, thanks.

Paolo