Remove DATA_MUTEX_CHECK(!mutex().isHeld()); from the DataMutexLocker constructor, introduced in r278248. Trying to lock a currently held mutex is not an error condition that should crash the process, it will just wait for its turn to lock it.
Created attachment 430725 [details] Patch
lgtm
Committed r278555 (238553@main): <https://commits.webkit.org/238553@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 430725 [details].
This change causes a test failure. Bug 227021 – [GTK] TestWTF:WTF_DataMutex.DoubleLockDeathTest is timing out