pageinspect: Fix memory context allocation of page in brin_revmap_data()

This caused the function to fail, as the aligned copy of the raw page
given by the function caller was not saved in the correct memory
context, which needs to be multi_call_memory_ctx in this case.

Issue introduced by 076f4d9.

Per buildfarm members sifika, mylodon and longfin.  I have reproduced
that locally with macos.

Discussion: https://postgr.es/m/YjFPOtfCW6yLXUeM@paquier.xyz
Backpatch-through: 10

diff --git a/contrib/pageinspect/brinfuncs.c b/contrib/pageinspect/brinfuncs.c
index 968d6cf6621febb7e964864ce94538467778bb85..efef8bc0af3e0c98fa472bac670e94c7a4498b18 100644 (file)
--- a/contrib/pageinspect/brinfuncs.c
+++ b/contrib/pageinspect/brinfuncs.c
@@ -374,15 +374,15 @@ brin_revmap_data(PG_FUNCTION_ARGS)
                MemoryContext mctx;
                Page            page;
 
-               /* minimally verify the page we got */
-               page = verify_brin_page(raw_page, BRIN_PAGETYPE_REVMAP, "revmap");
-
                /* create a function context for cross-call persistence */
                fctx = SRF_FIRSTCALL_INIT();
 
                /* switch to memory context appropriate for multiple function calls */
                mctx = MemoryContextSwitchTo(fctx->multi_call_memory_ctx);
 
+               /* minimally verify the page we got */
+               page = verify_brin_page(raw_page, BRIN_PAGETYPE_REVMAP, "revmap");
+
                state = palloc(sizeof(*state));
                state->tids = ((RevmapContents *) PageGetContents(page))->rm_tids;
                state->idx = 0;