Fix use-after-free introduced in 55ed3defc966

Evidenced by failure under RELCACHE_FORCE_RELEASE (buildfarm member
prion).

Author: Amit Langote
Discussion: https://postgr.es/m/CA+HiwqGV=k_Eh4jBiQw66ivvdG+EUkrEYeHTYL1SvDj_YOYV0g@mail.gmail.com

diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 11370c65906f945686892dd4debd48489e07710d..1faaaf625d9f207c1445dd375c4f797777455127 100644 (file)
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -896,13 +896,11 @@ DefineIndex(Oid relationId,
 
                        memcpy(part_oids, partdesc->oids, sizeof(Oid) * nparts);
 
-                       parentDesc = CreateTupleDescCopy(RelationGetDescr(rel));
+                       parentDesc = RelationGetDescr(rel);
                        opfamOids = palloc(sizeof(Oid) * numberOfKeyAttributes);
                        for (i = 0; i < numberOfKeyAttributes; i++)
                                opfamOids[i] = get_opclass_family(classObjectId[i]);
 
-                       heap_close(rel, NoLock);
-
                        /*
                         * For each partition, scan all existing indexes; if one matches
                         * our index definition and is not already attached to some other
@@ -1100,13 +1098,12 @@ DefineIndex(Oid relationId,
                                heap_freetuple(newtup);
                        }
                }
-               else
-                       heap_close(rel, NoLock);
 
                /*
                 * Indexes on partitioned tables are not themselves built, so we're
                 * done here.
                 */
+               heap_close(rel, NoLock);
                return address;
        }