Description: bpf: fix branch pruning logic
References:
 https://www.spinics.net/lists/stable/msg206984.html
Notes:
 carnil> Introduced by 17a5267067f3c372fec9ffb798d6eaba6b5e6a4c in 3.18-rc1
 carnil> for linux-4.14.y fixed in 2b3ea8ceb2bb71e9e58527661261dba127137d9b (4.14.9)
Bugs:
upstream: released (4.15-rc1) [c131187db2d3fa2f8bf32fdf4e9a4ef805168467]
4.9-upstream-stable: released (4.9.72) [7b5b73ea87a06236fa124bdebed1390d362d3439]
3.16-upstream-stable: N/A "Vulnerable code introduced in 3.18-rc1"
3.2-upstream-stable: N/A "Vulnerable code introduced in 3.18-rc1"
sid: released (4.14.7-1) [bugfix/all/bpf-fix-branch-pruning-logic.patch]
4.9-stretch-security: released (4.9.65-3+deb9u1) [bugfix/all/bpf-fix-branch-pruning-logic.patch]
3.16-jessie-security: N/A "Vulnerable code not present"
3.2-wheezy-security: N/A "Vulnerable code not present"