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authorChristian Borntraeger <borntraeger@de.ibm.com>2017-12-21 09:18:22 +0100
committerChristian Borntraeger <borntraeger@de.ibm.com>2017-12-22 15:22:41 +0100
commitc2cf265d860882b51a200e4a7553c17827f2b730 (patch)
tree2383bf77fda6cc74aba2c3d11f3fd9084c003011
parentKVM: s390: fix cmma migration for multiple memory slots (diff)
downloadlinux-c2cf265d860882b51a200e4a7553c17827f2b730.tar.xz
linux-c2cf265d860882b51a200e4a7553c17827f2b730.zip
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: David Hildenbrand <david@redhat.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: stable@vger.kernel.org # 4.13+ Fixes: 190df4a212a7 (KVM: s390: CMMA tracking, ESSA emulation, migration mode) Reviewed-by: Cornelia Huck <cohuck@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com>
-rw-r--r--arch/s390/kvm/priv.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
index 572496c688cc..0714bfa56da0 100644
--- a/arch/s390/kvm/priv.c
+++ b/arch/s390/kvm/priv.c
@@ -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);