I see this when I run the regression tests with valgrind (memcheck) on master's tip:
2014-03-25 22:38:40.850 PDT 31570 LOG: statement: SET enable_seqscan=OFF; 2014-03-25 22:38:40.859 PDT 31570 LOG: statement: SELECT count(*) FROM test_tsvector WHERE a @@ 'wr|qh'; ==31570== Conditional jump or move depends on uninitialised value(s) ==31570== at 0x8A58F4: gin_tsquery_triconsistent (tsginidx.c:329) ==31570== by 0x8F8659: FunctionCall7Coll (fmgr.c:1471) ==31570== by 0x488F20: directTriConsistentFn (ginlogic.c:97) ==31570== by 0x480026: keyGetItem (ginget.c:1094) ==31570== by 0x480191: scanGetItem (ginget.c:1182) ==31570== by 0x481A11: gingetbitmap (ginget.c:1791) ==31570== by 0x8F7F7E: FunctionCall2Coll (fmgr.c:1324) ==31570== by 0x4C8406: index_getbitmap (indexam.c:651) ==31570== by 0x663A46: MultiExecBitmapIndexScan (nodeBitmapIndexscan.c:89) ==31570== by 0x64C516: MultiExecProcNode (execProcnode.c:550) ==31570== by 0x662944: BitmapHeapNext (nodeBitmapHeapscan.c:104) ==31570== by 0x657739: ExecScanFetch (execScan.c:82) ==31570== Uninitialised value was created by a stack allocation ==31570== at 0x8A585B: gin_tsquery_triconsistent (tsginidx.c:299) It looks like a "recheck" stack variable isn't every being set within TS_execute_ternary() (which has a pointer to that variable on the stack) - ultimately, the checkcondition_gin() callback will set the flag, but only to 'true' (iff that's appropriate). When that doesn't happen, it just contains a garbage uninitialized value, and yet evidently control flow depends on that value. I propose that we initialize the variable to false, since there appears to be a tacit assumption that that is already the case, as with the plain consistent GIN support function in the same file. Attached patch does just that. -- Peter Geoghegan
*** a/src/backend/utils/adt/tsginidx.c --- b/src/backend/utils/adt/tsginidx.c *************** gin_tsquery_triconsistent(PG_FUNCTION_AR *** 305,311 **** /* int32 nkeys = PG_GETARG_INT32(3); */ Pointer *extra_data = (Pointer *) PG_GETARG_POINTER(4); GinLogicValue res = GIN_FALSE; ! bool recheck; /* The query requires recheck only if it involves weights */ if (query->size > 0) --- 305,311 ---- /* int32 nkeys = PG_GETARG_INT32(3); */ Pointer *extra_data = (Pointer *) PG_GETARG_POINTER(4); GinLogicValue res = GIN_FALSE; ! bool recheck = false; /* The query requires recheck only if it involves weights */ if (query->size > 0)
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