From 0fb9e4ace5ce4d479d839a720f32b99fdc87f455 Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Mon, 18 Sep 2017 17:43:37 -0700 Subject: [PATCH] Fix uninitialized variable in dshash.c. A bugfix for commit 8c0d7bafad36434cb08ac2c78e69ae72c194ca20. The code would have crashed if hashtable->size_log2 ever had the same value as hashtable->control->size_log2 by coincidence. Per Valgrind. Author: Thomas Munro Reported-By: Tomas Vondra Discussion: https://postgr.es/m/e72fb33c-4f31-f276-e972-263d9b59554d%402ndquadrant.com --- src/backend/lib/dshash.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/src/backend/lib/dshash.c b/src/backend/lib/dshash.c index 448e058725..dd87573067 100644 --- a/src/backend/lib/dshash.c +++ b/src/backend/lib/dshash.c @@ -249,6 +249,7 @@ dshash_create(dsa_area *area, const dshash_parameters *params, void *arg) } hash_table->buckets = dsa_get_address(area, hash_table->control->buckets); + hash_table->size_log2 = hash_table->control->size_log2; return hash_table; } @@ -280,6 +281,14 @@ dshash_attach(dsa_area *area, const dshash_parameters *params, hash_table->find_exclusively_locked = false; Assert(hash_table->control->magic == DSHASH_MAGIC); + /* + * These will later be set to the correct values by + * ensure_valid_bucket_pointers(), at which time we'll be holding a + * partition lock for interlocking against concurrent resizing. + */ + hash_table->buckets = NULL; + hash_table->size_log2 = 0; + return hash_table; }