postgres.git / summary / log / commit / refs

commit    55416b26a98fcf354af88cdd27fc2e045453b68a
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Tue Nov 03 21:16:36 2020 +0000
First released in: 14.0, 10.15, 11.10, 12.5, 13.1

    Guard against core dump from uninitialized subplan.
    
    If the planner erroneously puts a non-parallel-safe SubPlan into
    a parallelized portion of the query tree, nodeSubplan.c will fail
    in the worker processes because it finds a null in es_subplanstates,
    which it's unable to cope with.  It seems worth a test-and-elog to
    make that an error case rather than a core dump case.
    
    This probably should have been included in commit 16ebab688, which
    was responsible for allowing nulls to appear in es_subplanstates
    to begin with.  So, back-patch to v10 where that came in.
    
    Discussion: https://postgr.es/m/924226.1604422326@sss.pgh.pa.us


 src/backend/executor/nodeSubplan.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/backend/executor/nodeSubplan.c b/src/backend/executor/nodeSubplan.c
index 5e9ce229b89..62ef1385710 100644
--- a/src/backend/executor/nodeSubplan.c
+++ b/src/backend/executor/nodeSubplan.c
@@ -798,7 +798,15 @@ ExecInitSubPlan(SubPlan *subplan, PlanState *parent)
 	sstate->planstate = (PlanState *) list_nth(estate->es_subplanstates,
 											   subplan->plan_id - 1);
 
-	/* ... and to its parent's state */
+	/*
+	 * This check can fail if the planner mistakenly puts a parallel-unsafe
+	 * subplan into a parallelized subquery; see ExecSerializePlan.
+	 */
+	if (sstate->planstate == NULL)
+		elog(ERROR, "subplan \"%s\" was not initialized",
+			 subplan->plan_name);
+
+	/* Link to parent's state, too */
 	sstate->parent = parent;
 
 	/* Initialize subexpressions */


[parent: 136f87ea57b3]