From 7c5d57caed4d8af705d0cc3131d0d8ed72b7a41d Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Mon, 1 Feb 2021 02:03:59 -0500 Subject: [PATCH] Fix portability issue in new jsonbsubs code. On machines where sizeof(Datum) > sizeof(Oid) (that is, any 64-bit platform), the previous coding would compute a misaligned workspace->index pointer if nupper is odd. Architectures where misaligned access is a hard no-no would then fail. This appears to explain why thorntail is unhappy but other buildfarm members are not. --- src/backend/utils/adt/jsonbsubs.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/src/backend/utils/adt/jsonbsubs.c b/src/backend/utils/adt/jsonbsubs.c index 491e27cc04b..cfb923aaa35 100644 --- a/src/backend/utils/adt/jsonbsubs.c +++ b/src/backend/utils/adt/jsonbsubs.c @@ -356,7 +356,7 @@ jsonb_subscript_fetch_old(ExprState *state, static void jsonb_exec_setup(const SubscriptingRef *sbsref, SubscriptingRefState *sbsrefstate, - SubscriptExecSteps * methods) + SubscriptExecSteps *methods) { JsonbSubWorkspace *workspace; ListCell *lc; @@ -368,9 +368,14 @@ jsonb_exec_setup(const SubscriptingRef *sbsref, nupper * (sizeof(Datum) + sizeof(Oid))); workspace->expectArray = false; ptr = ((char *) workspace) + MAXALIGN(sizeof(JsonbSubWorkspace)); - workspace->indexOid = (Oid *) ptr; - ptr += nupper * sizeof(Oid); + + /* + * This coding assumes sizeof(Datum) >= sizeof(Oid), else we might + * misalign the indexOid pointer + */ workspace->index = (Datum *) ptr; + ptr += nupper * sizeof(Datum); + workspace->indexOid = (Oid *) ptr; sbsrefstate->workspace = workspace; -- 2.39.5