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Commita26cc03

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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 parent75b4f93 commita26cc03

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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
@@ -273,10 +273,15 @@ static const dshash_parameters srtr_typmod_table_params = {
273273
/* hashtable for recognizing registered record types */
274274
staticHTAB*RecordCacheHash=NULL;
275275

276-
/* arrays of info about registered record types, indexed by assigned typmod */
277-
staticTupleDesc*RecordCacheArray=NULL;
278-
staticuint64*RecordIdentifierArray=NULL;
279-
staticint32RecordCacheArrayLen=0;/* allocated length of above arrays */
276+
typedefstructRecordCacheArrayEntry
277+
{
278+
uint64id;
279+
TupleDesctupdesc;
280+
}RecordCacheArrayEntry;
281+
282+
/* array of info about registered record types, indexed by assigned typmod */
283+
staticRecordCacheArrayEntry*RecordCacheArray=NULL;
284+
staticint32RecordCacheArrayLen=0;/* allocated length of above array */
280285
staticint32NextRecordTypmod=0;/* number of entries used */
281286

282287
/*
@@ -1703,25 +1708,20 @@ ensure_record_cache_typmod_slot_exists(int32 typmod)
17031708
{
17041709
if (RecordCacheArray==NULL)
17051710
{
1706-
RecordCacheArray= (TupleDesc*)
1707-
MemoryContextAllocZero(CacheMemoryContext,64*sizeof(TupleDesc));
1708-
RecordIdentifierArray= (uint64*)
1709-
MemoryContextAllocZero(CacheMemoryContext,64*sizeof(uint64));
1711+
RecordCacheArray= (RecordCacheArrayEntry*)
1712+
MemoryContextAllocZero(CacheMemoryContext,64*sizeof(RecordCacheArrayEntry));
17101713
RecordCacheArrayLen=64;
17111714
}
17121715

17131716
if (typmod >=RecordCacheArrayLen)
17141717
{
17151718
int32newlen=pg_nextpower2_32(typmod+1);
17161719

1717-
RecordCacheArray= (TupleDesc*)repalloc(RecordCacheArray,
1718-
newlen*sizeof(TupleDesc));
1720+
RecordCacheArray= (RecordCacheArrayEntry*)
1721+
repalloc(RecordCacheArray,
1722+
newlen*sizeof(RecordCacheArrayEntry));
17191723
memset(RecordCacheArray+RecordCacheArrayLen,0,
1720-
(newlen-RecordCacheArrayLen)*sizeof(TupleDesc));
1721-
RecordIdentifierArray= (uint64*)repalloc(RecordIdentifierArray,
1722-
newlen*sizeof(uint64));
1723-
memset(RecordIdentifierArray+RecordCacheArrayLen,0,
1724-
(newlen-RecordCacheArrayLen)*sizeof(uint64));
1724+
(newlen-RecordCacheArrayLen)*sizeof(RecordCacheArrayEntry));
17251725
RecordCacheArrayLen=newlen;
17261726
}
17271727
}
@@ -1759,8 +1759,8 @@ lookup_rowtype_tupdesc_internal(Oid type_id, int32 typmod, bool noError)
17591759
{
17601760
/* It is already in our local cache? */
17611761
if (typmod<RecordCacheArrayLen&&
1762-
RecordCacheArray[typmod]!=NULL)
1763-
returnRecordCacheArray[typmod];
1762+
RecordCacheArray[typmod].tupdesc!=NULL)
1763+
returnRecordCacheArray[typmod].tupdesc;
17641764

17651765
/* Are we attached to a shared record typmod registry? */
17661766
if (CurrentSession->shared_typmod_registry!=NULL)
@@ -1786,19 +1786,19 @@ lookup_rowtype_tupdesc_internal(Oid type_id, int32 typmod, bool noError)
17861786
* Our local array can now point directly to the TupleDesc
17871787
* in shared memory, which is non-reference-counted.
17881788
*/
1789-
RecordCacheArray[typmod]=tupdesc;
1789+
RecordCacheArray[typmod].tupdesc=tupdesc;
17901790
Assert(tupdesc->tdrefcount==-1);
17911791

17921792
/*
17931793
* We don't share tupdesc identifiers across processes, so
17941794
* assign one locally.
17951795
*/
1796-
RecordIdentifierArray[typmod]=++tupledesc_id_counter;
1796+
RecordCacheArray[typmod].id=++tupledesc_id_counter;
17971797

17981798
dshash_release_lock(CurrentSession->shared_typmod_table,
17991799
entry);
18001800

1801-
returnRecordCacheArray[typmod];
1801+
returnRecordCacheArray[typmod].tupdesc;
18021802
}
18031803
}
18041804
}
@@ -2011,10 +2011,10 @@ assign_record_type_typmod(TupleDesc tupDesc)
20112011
ensure_record_cache_typmod_slot_exists(entDesc->tdtypmod);
20122012
}
20132013

2014-
RecordCacheArray[entDesc->tdtypmod]=entDesc;
2014+
RecordCacheArray[entDesc->tdtypmod].tupdesc=entDesc;
20152015

20162016
/* Assign a unique tupdesc identifier, too. */
2017-
RecordIdentifierArray[entDesc->tdtypmod]=++tupledesc_id_counter;
2017+
RecordCacheArray[entDesc->tdtypmod].id=++tupledesc_id_counter;
20182018

20192019
/* Fully initialized; create the hash table entry */
20202020
recentry= (RecordCacheEntry*)hash_search(RecordCacheHash,
@@ -2063,10 +2063,10 @@ assign_record_type_identifier(Oid type_id, int32 typmod)
20632063
* It's a transient record type, so look in our record-type table.
20642064
*/
20652065
if (typmod >=0&&typmod<RecordCacheArrayLen&&
2066-
RecordCacheArray[typmod]!=NULL)
2066+
RecordCacheArray[typmod].tupdesc!=NULL)
20672067
{
2068-
Assert(RecordIdentifierArray[typmod]!=0);
2069-
returnRecordIdentifierArray[typmod];
2068+
Assert(RecordCacheArray[typmod].id!=0);
2069+
returnRecordCacheArray[typmod].id;
20702070
}
20712071

20722072
/* For anonymous or unrecognized record type, generate a new ID */
@@ -2146,7 +2146,7 @@ SharedRecordTypmodRegistryInit(SharedRecordTypmodRegistry *registry,
21462146
TupleDesctupdesc;
21472147
boolfound;
21482148

2149-
tupdesc=RecordCacheArray[typmod];
2149+
tupdesc=RecordCacheArray[typmod].tupdesc;
21502150
if (tupdesc==NULL)
21512151
continue;
21522152

‎src/tools/pgindent/typedefs.list‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -2218,6 +2218,7 @@ ReadLocalXLogPageNoWaitPrivate
22182218
ReadReplicationSlotCmd
22192219
ReassignOwnedStmt
22202220
RecheckForeignScan_function
2221+
RecordCacheArrayEntry
22212222
RecordCacheEntry
22222223
RecordCompareData
22232224
RecordIOData

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