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

Pierre Morel
2019-02-01T09:36:10Z

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@linux.ibm.com>
> Reported-by: Halil Pasic <pasic@linux.ibm.com>
> ---
> 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@linux.ibm.com>

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