Description: KVM: avoid NULL pointer dereference in kvm_dirty_ring_push
References:
 https://www.openwall.com/lists/oss-security/2022/04/07/1
 https://www.spinics.net/lists/kvm/msg273052.html
Notes:
 bwh> Introduced in 5.11-rc1 by commit fb04a1eddb1a "KVM: X86: Implement
 bwh> ring-based dirty memory tracking". Fix is currently in next as
 bwh> commit 5593473a1e6c "KVM: avoid NULL pointer dereference in
 bwh> kvm_dirty_ring_push".
 carnil> For 5.17.y fixed as well in 5.17.3
Bugs:
upstream: released (5.18-rc3) [5593473a1e6c743764b08e3b6071cb43b5cfa6c4]
5.10-upstream-stable: N/A "Vulnerable code not present"
4.19-upstream-stable: N/A "Vulnerable code not present"
4.9-upstream-stable: N/A "Vulnerable code not present"
sid: released (5.17.3-1)
5.10-bullseye-security: N/A "Vulnerable code not present"
4.19-buster-security: N/A "Vulnerable code not present"
4.9-stretch-security: N/A "Vulnerable code not present"