From be80954688c406122b560161192cc1d2e64e3757 Mon Sep 17 00:00:00 2001 From: Andreas Seltenreich Date: Mon, 5 Dec 2016 20:46:28 +0100 Subject: [PATCH] Fix potential crash on ReScanGather. Initialize gatherstate->nextreader to 0 in order to prevent a crash when ReScanGather gets less workers than the original scan, leading to nextreader pointing outside the readers[nworkers] array. --- src/backend/executor/nodeGather.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/src/backend/executor/nodeGather.c b/src/backend/executor/nodeGather.c index 880ca62..2bdf223 100644 --- a/src/backend/executor/nodeGather.c +++ b/src/backend/executor/nodeGather.c @@ -173,6 +173,7 @@ ExecGather(GatherState *node) if (pcxt->nworkers_launched > 0) { node->nreaders = 0; + node->nextreader = 0; node->reader = palloc(pcxt->nworkers_launched * sizeof(TupleQueueReader *)); @@ -335,6 +336,7 @@ gather_readnext(GatherState *gatherstate) CHECK_FOR_INTERRUPTS(); /* Attempt to read a tuple, but don't block if none is available. */ + Assert(gatherstate->nextreader < gatherstate->nreaders); reader = gatherstate->reader[gatherstate->nextreader]; tup = TupleQueueReaderNext(reader, true, &readerdone); -- 2.10.2