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Commit189097d

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Fix exception safety bug in typcache.c.
If an out-of-memory error was thrown at an unfortunate time,ensure_record_cache_typmod_slot_exists() could leak memory and leavebehind a global state that produced an infinite loop on the next call.Fix by merging RecordCacheArray and RecordIdentifierArray into a singlearray. With only one allocation or re-allocation, there is nointermediate state.Back-patch to all supported releases.Reported-by: "James Pang (chaolpan)" <chaolpan@cisco.com>Reviewed-by: Michael Paquier <michael@paquier.xyz>Discussion:https://postgr.es/m/PH0PR11MB519113E738814BDDA702EDADD6EFA%40PH0PR11MB5191.namprd11.prod.outlook.com
1 parentc570bb4 commit189097d

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2 files changed

+27
-26
lines changed

2 files changed

+27
-26
lines changed

‎src/backend/utils/cache/typcache.c

Lines changed: 26 additions & 26 deletions
Original file line numberDiff line numberDiff line change
@@ -271,10 +271,15 @@ static const dshash_parameters srtr_typmod_table_params = {
271271
/* hashtable for recognizing registered record types */
272272
staticHTAB*RecordCacheHash=NULL;
273273

274-
/* arrays of info about registered record types, indexed by assigned typmod */
275-
staticTupleDesc*RecordCacheArray=NULL;
276-
staticuint64*RecordIdentifierArray=NULL;
277-
staticint32RecordCacheArrayLen=0;/* allocated length of above arrays */
274+
typedefstructRecordCacheArrayEntry
275+
{
276+
uint64id;
277+
TupleDesctupdesc;
278+
}RecordCacheArrayEntry;
279+
280+
/* array of info about registered record types, indexed by assigned typmod */
281+
staticRecordCacheArrayEntry*RecordCacheArray=NULL;
282+
staticint32RecordCacheArrayLen=0;/* allocated length of above array */
278283
staticint32NextRecordTypmod=0;/* number of entries used */
279284

280285
/*
@@ -1583,10 +1588,8 @@ ensure_record_cache_typmod_slot_exists(int32 typmod)
15831588
{
15841589
if (RecordCacheArray==NULL)
15851590
{
1586-
RecordCacheArray= (TupleDesc*)
1587-
MemoryContextAllocZero(CacheMemoryContext,64*sizeof(TupleDesc));
1588-
RecordIdentifierArray= (uint64*)
1589-
MemoryContextAllocZero(CacheMemoryContext,64*sizeof(uint64));
1591+
RecordCacheArray= (RecordCacheArrayEntry*)
1592+
MemoryContextAllocZero(CacheMemoryContext,64*sizeof(RecordCacheArrayEntry));
15901593
RecordCacheArrayLen=64;
15911594
}
15921595

@@ -1597,14 +1600,11 @@ ensure_record_cache_typmod_slot_exists(int32 typmod)
15971600
while (typmod >=newlen)
15981601
newlen *=2;
15991602

1600-
RecordCacheArray= (TupleDesc*)repalloc(RecordCacheArray,
1601-
newlen*sizeof(TupleDesc));
1603+
RecordCacheArray= (RecordCacheArrayEntry*)
1604+
repalloc(RecordCacheArray,
1605+
newlen*sizeof(RecordCacheArrayEntry));
16021606
memset(RecordCacheArray+RecordCacheArrayLen,0,
1603-
(newlen-RecordCacheArrayLen)*sizeof(TupleDesc));
1604-
RecordIdentifierArray= (uint64*)repalloc(RecordIdentifierArray,
1605-
newlen*sizeof(uint64));
1606-
memset(RecordIdentifierArray+RecordCacheArrayLen,0,
1607-
(newlen-RecordCacheArrayLen)*sizeof(uint64));
1607+
(newlen-RecordCacheArrayLen)*sizeof(RecordCacheArrayEntry));
16081608
RecordCacheArrayLen=newlen;
16091609
}
16101610
}
@@ -1642,8 +1642,8 @@ lookup_rowtype_tupdesc_internal(Oid type_id, int32 typmod, bool noError)
16421642
{
16431643
/* It is already in our local cache? */
16441644
if (typmod<RecordCacheArrayLen&&
1645-
RecordCacheArray[typmod]!=NULL)
1646-
returnRecordCacheArray[typmod];
1645+
RecordCacheArray[typmod].tupdesc!=NULL)
1646+
returnRecordCacheArray[typmod].tupdesc;
16471647

16481648
/* Are we attached to a shared record typmod registry? */
16491649
if (CurrentSession->shared_typmod_registry!=NULL)
@@ -1669,19 +1669,19 @@ lookup_rowtype_tupdesc_internal(Oid type_id, int32 typmod, bool noError)
16691669
* Our local array can now point directly to the TupleDesc
16701670
* in shared memory, which is non-reference-counted.
16711671
*/
1672-
RecordCacheArray[typmod]=tupdesc;
1672+
RecordCacheArray[typmod].tupdesc=tupdesc;
16731673
Assert(tupdesc->tdrefcount==-1);
16741674

16751675
/*
16761676
* We don't share tupdesc identifiers across processes, so
16771677
* assign one locally.
16781678
*/
1679-
RecordIdentifierArray[typmod]=++tupledesc_id_counter;
1679+
RecordCacheArray[typmod].id=++tupledesc_id_counter;
16801680

16811681
dshash_release_lock(CurrentSession->shared_typmod_table,
16821682
entry);
16831683

1684-
returnRecordCacheArray[typmod];
1684+
returnRecordCacheArray[typmod].tupdesc;
16851685
}
16861686
}
16871687
}
@@ -1892,10 +1892,10 @@ assign_record_type_typmod(TupleDesc tupDesc)
18921892
ensure_record_cache_typmod_slot_exists(entDesc->tdtypmod);
18931893
}
18941894

1895-
RecordCacheArray[entDesc->tdtypmod]=entDesc;
1895+
RecordCacheArray[entDesc->tdtypmod].tupdesc=entDesc;
18961896

18971897
/* Assign a unique tupdesc identifier, too. */
1898-
RecordIdentifierArray[entDesc->tdtypmod]=++tupledesc_id_counter;
1898+
RecordCacheArray[entDesc->tdtypmod].id=++tupledesc_id_counter;
18991899

19001900
/* Fully initialized; create the hash table entry */
19011901
recentry= (RecordCacheEntry*)hash_search(RecordCacheHash,
@@ -1944,10 +1944,10 @@ assign_record_type_identifier(Oid type_id, int32 typmod)
19441944
* It's a transient record type, so look in our record-type table.
19451945
*/
19461946
if (typmod >=0&&typmod<RecordCacheArrayLen&&
1947-
RecordCacheArray[typmod]!=NULL)
1947+
RecordCacheArray[typmod].tupdesc!=NULL)
19481948
{
1949-
Assert(RecordIdentifierArray[typmod]!=0);
1950-
returnRecordIdentifierArray[typmod];
1949+
Assert(RecordCacheArray[typmod].id!=0);
1950+
returnRecordCacheArray[typmod].id;
19511951
}
19521952

19531953
/* For anonymous or unrecognized record type, generate a new ID */
@@ -2027,7 +2027,7 @@ SharedRecordTypmodRegistryInit(SharedRecordTypmodRegistry *registry,
20272027
TupleDesctupdesc;
20282028
boolfound;
20292029

2030-
tupdesc=RecordCacheArray[typmod];
2030+
tupdesc=RecordCacheArray[typmod].tupdesc;
20312031
if (tupdesc==NULL)
20322032
continue;
20332033

‎src/tools/pgindent/typedefs.list

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -2019,6 +2019,7 @@ ReadExtraTocPtrType
20192019
ReadFunc
20202020
ReassignOwnedStmt
20212021
RecheckForeignScan_function
2022+
RecordCacheArrayEntry
20222023
RecordCacheEntry
20232024
RecordCompareData
20242025
RecordIOData

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