This patch avoids gcc issuing the following warning when KVM_MAX_VCPUS=1: warning: array subscript is above array bounds kvm_for_each_vcpu currently checks to see if the index for the vcpu is valid /after/ loading it. We don't run into problems because the address is still inside the enclosing struct kvm and we never deference or write to it, so this isn't a security issue. The warning occurs when KVM_MAX_VCPUS=1 because the increment portion of the loop will *always* cause the loop to load an invalid location since ++idx will always be > 0. This patch moves the load so that the check occurs before the load and we don't run into the compiler warning. Signed-off-by: Neil Brown <neilb@xxxxxxx> Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx> --- include/linux/kvm_host.h | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -292,9 +292,10 @@ static inline struct kvm_vcpu *kvm_get_v } #define kvm_for_each_vcpu(idx, vcpup, kvm) \ - for (idx = 0, vcpup = kvm_get_vcpu(kvm, idx); \ - idx < atomic_read(&kvm->online_vcpus) && vcpup; \ - vcpup = kvm_get_vcpu(kvm, ++idx)) + for (idx = 0; \ + idx < atomic_read(&kvm->online_vcpus) && \ + (vcpup = kvm_get_vcpu(kvm, idx)) != NULL; \ + idx++) int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id); void kvm_vcpu_uninit(struct kvm_vcpu *vcpu); -- Jeff Mahoney SUSE Labs -- 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
