Re: BUG #17591: elog(ERROR) cause SharedSnapshotLock deadlock

The following bug has been logged on the website:

Bug reference: 17591
Logged by: ma liangzhu
Email address: ma100@hotmail.com
PostgreSQL version: 14.5
Operating system: centos7
Description:

in lock.c, we can see code Release lock before return , e.g.

```c
996: LockAcquireExtended
{
LWLockAcquire(partitionLock, LW_EXCLUSIVE);

proclock = SetupLockInTable( );
if (!proclock)
{
LWLockRelease(partitionLock); --- Release lock before return
ereport(ERROR,)
}
}
```

bug we can see some code doesn't release the lock. Does it may cause
deadlock?

```c
LockRelease()
{
LWLockAcquire(partitionLock, LW_EXCLUSIVE);

lock = locallock->lock;
if (!lock)
{
lock = (LOCK *) hash_search_with_hash_value( );
if (!lock)
2126: elog(ERROR, "failed to re-find shared lock object"); -- exit
without release
}
```