[GIT,PULL,16/18] KVM: s390: fix possible null pointer dereference in pending_irqs()
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Message ID 1550835749-26436-17-git-send-email-frankja@linux.ibm.com
State New
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Series
  • [GIT,PULL,01/18] KVM: s390: clarify kvm related kernel message
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Commit Message

Janosch Frank Feb. 22, 2019, 11:42 a.m. UTC
From: Michael Mueller <mimu@linux.ibm.com>

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>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Message-Id: <20190131085247.13826-16-mimu@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
 arch/s390/kvm/interrupt.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

Patch
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diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index dc44620..8216286 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)