Commit c2cf265d authored by Christian Borntraeger's avatar Christian Borntraeger
Browse files

KVM: s390: prevent buffer overrun on memory hotplug during migration



We must not go beyond the pre-allocated buffer. This can happen when
a new memory slot is added during migration.

Reported-by: default avatarDavid Hildenbrand <david@redhat.com>
Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
Cc: stable@vger.kernel.org # 4.13+
Fixes: 190df4a2

 (KVM: s390: CMMA tracking, ESSA emulation, migration mode)
Reviewed-by: default avatarCornelia Huck <cohuck@redhat.com>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
parent 32aa144f
......@@ -1006,7 +1006,7 @@ 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);
......
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