Description: vhost: make sure log_num < in_num
References:
 https://www.openwall.com/lists/oss-security/2019/09/17/1
 https://blade.tencent.com/en/advisories/v-ghost/
Notes:
 carnil> commit fixes 3a4d5c94e959 ("vhost_net: a kernel-level virtio
 carnil> server") present in all supported releases.
Bugs:
upstream: released (5.3) [060423bfdee3f8bc6e2c1bac97de24d5415e2bc4]
4.19-upstream-stable: released (4.19.73) [ba03ee62aed0b0ee2eadfeb4a2fecc7d7eb47871]
4.9-upstream-stable: released (4.9.193) [8d8276867b5ac539f1d6e166a028b51c8b1ceda8]
3.16-upstream-stable: released (3.16.74) [8041c3ee83638f34d4c6b52f432601ad12ea4850]
sid: released (5.2.17-1)
4.19-buster-security: released (4.19.67-2+deb10u1) [bugfix/all/vhost-make-sure-log_num-in_num.patch]
4.9-stretch-security: released (4.9.189-3+deb9u1) [bugfix/all/vhost-make-sure-log_num-in_num.patch]
3.16-jessie-security: released (3.16.74-1)