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


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