Description: fget: check that the fd still exists after getting a ref to it
References:
 https://bugzilla.redhat.com/show_bug.cgi?id=2029923
 https://bugs.chromium.org/p/project-zero/issues/detail?id=2247
Notes:
 carnil> Fixed as weil in 5.15.7 for 5.15.y.
Bugs:
upstream: released (5.16-rc4) [054aa8d439b9185d4f5eb9a90282d1ce74772969]
5.10-upstream-stable: released (5.10.84) [4baba6ba56eb91a735a027f783cc4b9276b48d5b]
4.19-upstream-stable: released (4.19.220) [8bf31f9d9395b71af3ed33166a057cd3ec0c59da]
4.9-upstream-stable: released (4.9.292) [a043f5a600052dc93bc3d7a6a2c1592b6ee77482]
sid: released (5.15.5-2) [bugfix/all/fget-check-that-the-fd-still-exists-after-getting-a-.patch]
5.10-bullseye-security: released (5.10.84-1)
4.19-buster-security: released (4.19.232-1)
4.9-stretch-security: released (4.9.303-1)