We must not go beyond the pre-allocated buffer. This can happen when
a new memory slot is added during migration.
Reported-by: David Hildenbrand <david@xxxxxxxxxx>
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # 4.13+
Fixes: 190df4a212a7 (KVM: s390: CMMA tracking, ESSA emulation, migration mode)
---
arch/s390/kvm/priv.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index c954ac49eee4..3211bf58d838 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -1002,7 +1002,7 @@ static inline int do_essa(struct kvm_vcpu *vcpu, const int orc)
cbrlo[entries] = gfn << PAGE_SHIFT;
}
- if (orc) {
+ if (orc && gfn < ms->bitmap_size) {
/* increment only if we are really flipping the bit to 1 */
if (!test_and_set_bit(gfn, ms->pgste_bitmap))
atomic64_inc(&ms->dirty_pages);
--
2.13.4
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