Commit 77bbeea7 authored Dec 21, 2017 by Christian Borntraeger Committed by Greg Kroah-Hartman Jan 10, 2018

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: 190df4a2 (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>

parent 853bcade

arch/s390/kvm/priv.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1009,7 +1009,7 @@ 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);