Description: Indirect branch speculation can be enabled after it was force-disabled by the PR_SPEC_FORCE_DISABLE prctl command.
References:
 https://lkml.org/lkml/2020/6/9/184
 https://www.openwall.com/lists/oss-security/2020/06/10/1
 https://bugzilla.redhat.com/show_bug.cgi?id=1845868
Notes:
 carnil> Commit fixes 9137bb27e60e ("x86/speculation: Add prctl()
 carnil> control for indirect branch speculation")
Bugs:
upstream: released (5.8-rc1) [4d8df8cbb9156b0a0ab3f802b80cb5db57acc0bf]
4.19-upstream-stable: released (4.19.129) [52c419ba4c96880abd61b38e6e08e4ecd17350f3]
4.9-upstream-stable: released (4.9.228) [db39004352a40107213a70dc8e549936a6468fa9]
3.16-upstream-stable: ignored "EOL"
sid: released (5.7.6-1)
4.19-buster-security: released (4.19.131-1)
4.9-stretch-security: released (4.9.228-1)
3.16-jessie-security: ignored "EOL"