General help

Have always hated the 'numbers' on permissions ... can never remember which sets what.

So what does the following look like on your server:

ls -ld /var/www/moodledata

Like this?

drwxrwsrwx. 11 apache apache 4096 Jun 25 16:32 moodledata

Recursively, where, if present due to config, is where one would fine a 'lock' directory.  Like this?

drwxrwsrwx.  3 apache apache 4096 Jun 25 16:33 cache
drwxrwsrwx. 17 apache apache 4096 Jun 25 10:01 filedir
drwxrwsrwx.  2 apache apache 4096 Jun 22 12:32 lang
drwxrwsrwx.  7 apache apache 4096 Jun 25 17:10 localcache
drwxrwsrwx.  6 apache apache 4096 Jun 25 10:01 models
drwxrwsrwx.  2 apache apache 4096 Jun 22 12:34 muc
drwxrwsrwx.  2 apache apache 4096 Jun 26 00:01 sessions
drwxrwsrwx.  9 apache apache 4096 Jun 25 16:33 temp
drwxrwsrwx.  3 apache apache 4096 Jun 25 10:01 trashdir

Note there is no 'lock' directory.

In config-dist.php of a fresh git acquired 3.9+ (Build: 20200626)
There are several config lines related to your issue.

Clips:

// Some filesystems such as NFS may not support file locking operations.
//     $CFG->preventfilelocking = false;
// Moodle 2.7 introduces a locking api for critical tasks (e.g. cron).
// The default locking system to use is DB locking for Postgres, MySQL, MariaDB and
// file locking for Oracle and SQLServer. If $CFG->preventfilelocking is set, then the
// default will always be DB locking. It can be manually set to one of the lock
// \core\lock\lock_factory interface.
//      $CFG->lock_factory = "auto";
// The list of available lock factories is:
// "\\core\\lock\\file_lock_factory" - File locking
//      Uses lock files stored by default in the dataroot. Whether this
// "\\core\\lock\\db_record_lock_factory" - DB locking based on table rows.
// "\\core\\lock\\mysql_lock_factory" - DB locking based on MySQL / MariaDB locks.
// "\\core\\lock\\postgres_lock_factory" - DB locking based on postgres advisory locks.
// Settings used by the lock factories
// Location for lock files used by the File locking factory. This must exist
// on a shared file system that supports locking.
//      $CFG->file_lock_root = $CFG->dataroot . '/lock';
// Session lock warning threshold. Long running pages should release the session using \core\session\manager::write_close().
// Set this threshold to any value greater than 0 to add developer warnings when a page locks the session for too long.
// The session should rarely be locked for more than 1 second. The input should be in seconds and may be a float.
//      $CFG->debugsessionlock = 5;

Your errors show it started Execute adhoc task: core_course\task\course_delete_modules and couldn't.

'destruct' ... which means to me, erase/remove.

Since you have no lock directory in moodledata, has to be in DB ... and there is a table for locks.   I've never had to use it.

mysql> show tables like 'mdl_lock%';

My 3.9 DB has the table but no data in it!

mysql> select * from mdl_lock_db;
Empty set (0.00 sec)

For some reason, your server is confused.

Suggest using config.php and setting

//      $CFG->file_lock_root = $CFG->dataroot . '/lock';

which, if I understand it, should create a lock directory in moodledata.

If it doesn't, manually create a 'lock' directory in your moodledata and give it liberal permissions:

mkdir lock

chmod ugo+rwx lock -R

chown apache:apache lock -R

should look like:

drwxrwsrwx.  9 apache apache 4096 Jun 25 16:33 lock

The run the adhoc task again to see if we can't get by that!

Fingers X'd!

'SoS', Ken