KVM: s390: prevent buffer overrun on memory hotplug during migration
commit c2cf265d860882b51a200e4a7553c17827f2b730 upstream.
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@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Fixes: 190df4a212a7 (KVM: s390: CMMA tracking, ESSA emulation, migration mode)
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index 5b25287..7bd3a59 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -1009,7 +1009,7 @@
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);
