Symfony version(s) affected

v5.4.0-BETA1

Description

In some cases the lock component fails to acquire a semaphore. In this scenario it will try to remove a non existent semaphore, which results in a PHP warning:

sem_remove(): SysV semaphore [id] does not (any longer) exist.

This seems to be related to the recent change in 5.4 to use semaphores instead of flock in the LockRegistry

How to reproduce

PHP Version: 7.4

On my machine the acquiring failure can be reproduced in this scenario:

Have two concurrent processes: Process A and Process B

1. Process A wins the lock race and acquires a semaphore
2. Process B will not acquire a lock, but will wait until the semaphore becomes available again (acquire in blocking mode)
3. Process A will remove the the semaphore at the end of the request.
4. Process B will continue, but the acquiring fails since the semaphore is removed in Process A
5. Process B will try to remove the semaphore, but since it does not exist this results in the PHP warning

Possible Solution

No response

Additional Context

No response