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Commite2452c2

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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 parentf7d2511 commite2452c2

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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
@@ -272,10 +272,15 @@ static const dshash_parameters srtr_typmod_table_params = {
272272
/* hashtable for recognizing registered record types */
273273
staticHTAB*RecordCacheHash=NULL;
274274

275-
/* arrays of info about registered record types, indexed by assigned typmod */
276-
staticTupleDesc*RecordCacheArray=NULL;
277-
staticuint64*RecordIdentifierArray=NULL;
278-
staticint32RecordCacheArrayLen=0;/* allocated length of above arrays */
275+
typedefstructRecordCacheArrayEntry
276+
{
277+
uint64id;
278+
TupleDesctupdesc;
279+
}RecordCacheArrayEntry;
280+
281+
/* array of info about registered record types, indexed by assigned typmod */
282+
staticRecordCacheArrayEntry*RecordCacheArray=NULL;
283+
staticint32RecordCacheArrayLen=0;/* allocated length of above array */
279284
staticint32NextRecordTypmod=0;/* number of entries used */
280285

281286
/*
@@ -1702,10 +1707,8 @@ ensure_record_cache_typmod_slot_exists(int32 typmod)
17021707
{
17031708
if (RecordCacheArray==NULL)
17041709
{
1705-
RecordCacheArray= (TupleDesc*)
1706-
MemoryContextAllocZero(CacheMemoryContext,64*sizeof(TupleDesc));
1707-
RecordIdentifierArray= (uint64*)
1708-
MemoryContextAllocZero(CacheMemoryContext,64*sizeof(uint64));
1710+
RecordCacheArray= (RecordCacheArrayEntry*)
1711+
MemoryContextAllocZero(CacheMemoryContext,64*sizeof(RecordCacheArrayEntry));
17091712
RecordCacheArrayLen=64;
17101713
}
17111714

@@ -1716,14 +1719,11 @@ ensure_record_cache_typmod_slot_exists(int32 typmod)
17161719
while (typmod >=newlen)
17171720
newlen *=2;
17181721

1719-
RecordCacheArray= (TupleDesc*)repalloc(RecordCacheArray,
1720-
newlen*sizeof(TupleDesc));
1722+
RecordCacheArray= (RecordCacheArrayEntry*)
1723+
repalloc(RecordCacheArray,
1724+
newlen*sizeof(RecordCacheArrayEntry));
17211725
memset(RecordCacheArray+RecordCacheArrayLen,0,
1722-
(newlen-RecordCacheArrayLen)*sizeof(TupleDesc));
1723-
RecordIdentifierArray= (uint64*)repalloc(RecordIdentifierArray,
1724-
newlen*sizeof(uint64));
1725-
memset(RecordIdentifierArray+RecordCacheArrayLen,0,
1726-
(newlen-RecordCacheArrayLen)*sizeof(uint64));
1726+
(newlen-RecordCacheArrayLen)*sizeof(RecordCacheArrayEntry));
17271727
RecordCacheArrayLen=newlen;
17281728
}
17291729
}
@@ -1761,8 +1761,8 @@ lookup_rowtype_tupdesc_internal(Oid type_id, int32 typmod, bool noError)
17611761
{
17621762
/* It is already in our local cache? */
17631763
if (typmod<RecordCacheArrayLen&&
1764-
RecordCacheArray[typmod]!=NULL)
1765-
returnRecordCacheArray[typmod];
1764+
RecordCacheArray[typmod].tupdesc!=NULL)
1765+
returnRecordCacheArray[typmod].tupdesc;
17661766

17671767
/* Are we attached to a shared record typmod registry? */
17681768
if (CurrentSession->shared_typmod_registry!=NULL)
@@ -1788,19 +1788,19 @@ lookup_rowtype_tupdesc_internal(Oid type_id, int32 typmod, bool noError)
17881788
* Our local array can now point directly to the TupleDesc
17891789
* in shared memory, which is non-reference-counted.
17901790
*/
1791-
RecordCacheArray[typmod]=tupdesc;
1791+
RecordCacheArray[typmod].tupdesc=tupdesc;
17921792
Assert(tupdesc->tdrefcount==-1);
17931793

17941794
/*
17951795
* We don't share tupdesc identifiers across processes, so
17961796
* assign one locally.
17971797
*/
1798-
RecordIdentifierArray[typmod]=++tupledesc_id_counter;
1798+
RecordCacheArray[typmod].id=++tupledesc_id_counter;
17991799

18001800
dshash_release_lock(CurrentSession->shared_typmod_table,
18011801
entry);
18021802

1803-
returnRecordCacheArray[typmod];
1803+
returnRecordCacheArray[typmod].tupdesc;
18041804
}
18051805
}
18061806
}
@@ -2010,10 +2010,10 @@ assign_record_type_typmod(TupleDesc tupDesc)
20102010
ensure_record_cache_typmod_slot_exists(entDesc->tdtypmod);
20112011
}
20122012

2013-
RecordCacheArray[entDesc->tdtypmod]=entDesc;
2013+
RecordCacheArray[entDesc->tdtypmod].tupdesc=entDesc;
20142014

20152015
/* Assign a unique tupdesc identifier, too. */
2016-
RecordIdentifierArray[entDesc->tdtypmod]=++tupledesc_id_counter;
2016+
RecordCacheArray[entDesc->tdtypmod].id=++tupledesc_id_counter;
20172017

20182018
/* Fully initialized; create the hash table entry */
20192019
recentry= (RecordCacheEntry*)hash_search(RecordCacheHash,
@@ -2062,10 +2062,10 @@ assign_record_type_identifier(Oid type_id, int32 typmod)
20622062
* It's a transient record type, so look in our record-type table.
20632063
*/
20642064
if (typmod >=0&&typmod<RecordCacheArrayLen&&
2065-
RecordCacheArray[typmod]!=NULL)
2065+
RecordCacheArray[typmod].tupdesc!=NULL)
20662066
{
2067-
Assert(RecordIdentifierArray[typmod]!=0);
2068-
returnRecordIdentifierArray[typmod];
2067+
Assert(RecordCacheArray[typmod].id!=0);
2068+
returnRecordCacheArray[typmod].id;
20692069
}
20702070

20712071
/* For anonymous or unrecognized record type, generate a new ID */
@@ -2145,7 +2145,7 @@ SharedRecordTypmodRegistryInit(SharedRecordTypmodRegistry *registry,
21452145
TupleDesctupdesc;
21462146
boolfound;
21472147

2148-
tupdesc=RecordCacheArray[typmod];
2148+
tupdesc=RecordCacheArray[typmod].tupdesc;
21492149
if (tupdesc==NULL)
21502150
continue;
21512151

‎src/tools/pgindent/typedefs.list

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -2125,6 +2125,7 @@ ReadExtraTocPtrType
21252125
ReadFunc
21262126
ReassignOwnedStmt
21272127
RecheckForeignScan_function
2128+
RecordCacheArrayEntry
21282129
RecordCacheEntry
21292130
RecordCompareData
21302131
RecordIOData

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