diff options
| author | Robert Haas <rhaas@postgresql.org> | 2016-08-16 13:23:32 -0400 |
|---|---|---|
| committer | Robert Haas <rhaas@postgresql.org> | 2016-08-16 13:28:10 -0400 |
| commit | 0aa1e9a44db0b8f8b08acadf2833c724489bd279 (patch) | |
| tree | beff9e11056a9e4cf4dc41145f585c84934ead7c | |
| parent | d95a7c3fbcfd5e65802f7fb0bee31a914160d9ed (diff) | |
| download | postgresql-0aa1e9a44db0b8f8b08acadf2833c724489bd279.tar.gz postgresql-0aa1e9a44db0b8f8b08acadf2833c724489bd279.zip | |
Fix possible crash due to incorrect allocation context.
Commit af33039317ddc4a0e38a02e2255c2bf453115fd2 aimed to reduce
leakage from tqueue.c, which is good. Unfortunately, by changing the
memory context in which all of gather_readnext() executes, it also
changed the context in which ExecShutdownGatherWorkers executes, which
is not good, because that function eventually causes a call to
ExecParallelRetrieveInstrumentation, which proceeds to allocate
planstate->worker_instrument in a short-lived context, causing a
crash.
Rushabh Lathia, reviewed by Amit Kapila and by me.
| -rw-r--r-- | src/backend/executor/execParallel.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/src/backend/executor/execParallel.c b/src/backend/executor/execParallel.c index 380d743f6ce..5aa6f023bf7 100644 --- a/src/backend/executor/execParallel.c +++ b/src/backend/executor/execParallel.c @@ -500,6 +500,7 @@ ExecParallelRetrieveInstrumentation(PlanState *planstate, int n; int ibytes; int plan_node_id = planstate->plan->plan_node_id; + MemoryContext oldcontext; /* Find the instumentation for this node. */ for (i = 0; i < instrumentation->num_plan_nodes; ++i) @@ -514,10 +515,19 @@ ExecParallelRetrieveInstrumentation(PlanState *planstate, for (n = 0; n < instrumentation->num_workers; ++n) InstrAggNode(planstate->instrument, &instrument[n]); - /* Also store the per-worker detail. */ + /* + * Also store the per-worker detail. + * + * Worker instrumentation should be allocated in the same context as + * the regular instrumentation information, which is the per-query + * context. Switch into per-query memory context. + */ + oldcontext = MemoryContextSwitchTo(planstate->state->es_query_cxt); ibytes = mul_size(instrumentation->num_workers, sizeof(Instrumentation)); planstate->worker_instrument = palloc(ibytes + offsetof(WorkerInstrumentation, instrument)); + MemoryContextSwitchTo(oldcontext); + planstate->worker_instrument->num_workers = instrumentation->num_workers; memcpy(&planstate->worker_instrument->instrument, instrument, ibytes); |