Hi Michael, Steven, and Ranier,
> Anyway, couldn't we flip the order of the operations in
pgstat_init_entry() so as we do first an allocation and avoid any inconsistency
in the shared state?
The issue is not only in pgstat_init_entry(). Currently it errors on OOM but
this doesn't prevent us from calling pgstat_lock_entry() through
pgstat_get_entry_ref() which accesses a non-initialized lock.
Here's the second version of the patch. Now we remove inserted hash entry
on OOM which would prevent accessing the entry
