AcquireRewriteLocks/acquireLocksOnSubLinks vs. rowsecurity

Hi,

The locking around rowsecurity policy expressions seems to be
insufficient:
SELECT * FROM document WHERE f_leak(dtitle) ORDER BY did;
WARNING:  RelationIdGetRelation(247984) without holding lock on the relation
WARNING:  relation_open(247984, NoLock) of relation "uaccount" without previously held lock

I don't know the relevant code well. But as far as I can see that's
because normally the expectation is that relevant locks have either been
taken by the parser or by AcquireRewriteLocks(). But before

static Query *
fireRIRrules(Query *parsetree, List *activeRIRs, bool forUpdatePushedDown)
{
...    /*     * Fetch any new security quals that must be applied to this RTE.     */
get_row_security_policies(parsetree,parsetree->commandType, rte,                              rt_index, &securityQuals,
&withCheckOptions,                             &hasRowSecurity, &hasSubLinks);
 
    if (securityQuals != NIL || withCheckOptions != NIL)    {               ...        if (hasSubLinks)        {
              ...            expression_tree_walker((Node *) securityQuals,
fireRIRonSubLink,(void *) activeRIRs);                       ...                       }
 
        rte->securityQuals = list_concat(securityQuals,                                         rte->securityQuals);

neither will have acquired relevant locks. The parser because it doesn't
know about rowsecurity, AcquireRewriteLocks/acquireLocksOnSubLinks
because rte->securityQuals wan't even set and range_table_walker() uses
that.

Istmt that something like            context.for_execute = true;            acquireLocksOnSubLinks((Node *)
securityQuals,&context);            acquireLocksOnSubLinks((Node *) withCheckOptions, &context);
 
needs to be added to that code.

Greetings,

Andres Freund