'len' is 'unsigned long' which is never less than zero. So need a related type cast for comparation. The related warning (when building ARM64 with allmodconfig): arch/arm64/kvm/../../../arch/arm/kvm/mmio.c:82:2: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits] Signed-off-by: Chen Gang <gang.chen@xxxxxxxxxxx> --- arch/arm/kvm/mmio.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/arch/arm/kvm/mmio.c b/arch/arm/kvm/mmio.c index b8e06b7..626dfc8 100644 --- a/arch/arm/kvm/mmio.c +++ b/arch/arm/kvm/mmio.c @@ -79,7 +79,7 @@ static int decode_hsr(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, } len = kvm_vcpu_dabt_get_as(vcpu); - if (unlikely(len < 0)) + if (unlikely((long)len < 0)) return len; is_write = kvm_vcpu_dabt_iswrite(vcpu); -- 1.7.7.6 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html