msr_global_mutex_lock: handle errors from apr_global_mutex_lock

[marcstern]

apr_global_mutex_lock is sometimes called with a lock that wasn't created (for any reason).
In this case, the pointer is null and apr_global_mutex_lock dereferences a null pointer, leading to a crash.
This PR creates a wrapper around apr_global_mutex_lock to handle checking that and correct logging.
Same for msr_global_mutex_unlock.

[marcstern]

#3255 acknowledged to be solved by the PR

[fzipi]

LGTM

[airween]

Before we merge, I want to check why the lock acquire was failed (see #3255 - the user reported that this issue came with the new version where we introduced this method).

[marcstern]

The problem was already happening in the previous versions. Looks to me linked to concurrency.

[airween]

The problem was already happening in the previous versions. Looks to me linked to concurrency.

May be - but now the audit.log is empty (with this patch too).

I think we should investigate this issue. I already installed FreeBSD and could reproduce the behavior, so I'm on it.

[marcstern]

the audit.log is empty, but you should have an entry in the error log (about the problem at creation time)

[airween]

the audit.log is empty, but you should have an entry in the error log (about the problem at creation time)

Indeed, but I think we should investigate the issue.

[airween]

Please see my comments.

[marcstern]

the audit.log is empty, but you should have an entry in the error log (about the problem at creation time)

Indeed, but I think we should investigate the issue.
Correct. We should open a new ticket for this I guess (or continue #3255)

[airween]

Indeed, but I think we should investigate the issue.
Correct. We should open a new ticket for this I guess (or continue #3255)

yes, I made some investigation - see my comment there.

[sonarcloud]

Quality Gate failed

Failed conditions
5.9% Duplication on New Code (required ≤ 3%)
B Maintainability Rating on New Code (required ≥ A)

See analysis details on SonarCloud

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[marcstern]

I propose to accept this PR first, then create one that doesn't use the temp filename, as it's not the right way to create a mutx, see https://lists.apache.org/thread/ykb26kg4lgcqnldvxwd9p6hv16fy4z9l

[airween]

I propose to accept this PR first, then create one that doesn't use the temp filename, as it's not the right way to create a mutx, see https://lists.apache.org/thread/ykb26kg4lgcqnldvxwd9p6hv16fy4z9l

Okay, I approved this PR and resolved all conversation. You can merge this PR now.

Implemented all requested changes but a comment