In cache/locks/file/lib.php (cachelock_file class), it seems to me there are some discrepancies.
According to their signature, the second formal parameter of the lock and unlock functions  is $ownerid.

125 public function lock($key, $ownerid, $block = false) { 

[...]

183 public function unlock($key, $ownerid, $forceunlock = false) {

[...] 

But in the calls to these two functions don't pass the $ownerid as effectif parameter. They pass a boolean (maybe intended to set $block value?).

141 $this->unlock($key, true); 

142 $result = $this->lock($key, false); 

This affects all versions since 2.4.11 (Build: 20140714).