Re: [PATCH v7 15/15] KVM: s390: fix possible null pointer dereference in pending_irqs()

[Pierre Morel]

On 31/01/2019 09:52, Michael Mueller wrote:
> Assure a GISA is in use before accessing the IPM to avoid a
> null pointer dereference issue.
>
> Signed-off-by: Michael Mueller <mimu@xxxxxxxxxxxxx>
> Reported-by: Halil Pasic <pasic@xxxxxxxxxxxxx>
> ---
>   arch/s390/kvm/interrupt.c | 10 +++++++---
>   1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
> index d322400ca587..660ec87b6e60 100644
> --- a/arch/s390/kvm/interrupt.c
> +++ b/arch/s390/kvm/interrupt.c
> @@ -329,9 +329,13 @@ static inline unsigned long pending_irqs_no_gisa(struct kvm_vcpu *vcpu)
>   
>   static inline unsigned long pending_irqs(struct kvm_vcpu *vcpu)
>   {
> -	return pending_irqs_no_gisa(vcpu) |
> -		gisa_get_ipm(vcpu->kvm->arch.gisa_int.origin) <<
> -			IRQ_PEND_IO_ISC_7;
> +	struct kvm_s390_gisa_interrupt *gi = &vcpu->kvm->arch.gisa_int;
> +	unsigned long pending_mask;
> +
> +	pending_mask = pending_irqs_no_gisa(vcpu);
> +	if (gi->origin)
> +		pending_mask |= gisa_get_ipm(gi->origin) << IRQ_PEND_IO_ISC_7;
> +	return pending_mask;
>   }
>   
>   static inline int isc_to_irq_type(unsigned long isc)
Reviewed-by: Pierre Morel<pmorel@xxxxxxxxxxxxx>


--
Pierre Morel
Linux/KVM/QEMU in BÃblingen - Germany