From 949e2e7c4f680ef86e93500ba4bee563ae4ce78e Mon Sep 17 00:00:00 2001 From: Robert Haas Date: Thu, 23 Mar 2023 12:52:33 -0400 Subject: [PATCH] amcheck: Fix a few bugs in new update chain validation. We shouldn't set successor[whatever] to an offset number that is less than FirstOffsetNumber or more than maxoff. We already avoided that for redirects, but not for CTID links. Allowing bad offset numbers into the successor[] array causes core dumps. We shouldn't use HeapTupleHeaderIsHotUpdated() because it checks stuff other than the status of the infomask2 bit HEAP_HOT_UPDATED. We only care about the status of that bit, not the other stuff that HeapTupleHeaderIsHotUpdated() checks. This mistake can cause verify_heapam() to report corruption when none is present. The first hunk of this patch was written by me. The other two were written by Andres Freund. This could probably do with more review before commit, but I'd like to try to get the buildfarm green again sooner rather than later. Discussion: http://postgr.es/m/20230322204552.s6cv3ybqkklhhybb@awork3.anarazel.de --- contrib/amcheck/verify_heapam.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/contrib/amcheck/verify_heapam.c b/contrib/amcheck/verify_heapam.c index 663fb65dee..1b8607c6cc 100644 --- a/contrib/amcheck/verify_heapam.c +++ b/contrib/amcheck/verify_heapam.c @@ -543,7 +543,8 @@ verify_heapam(PG_FUNCTION_ARGS) */ nextblkno = ItemPointerGetBlockNumber(&(ctx.tuphdr)->t_ctid); nextoffnum = ItemPointerGetOffsetNumber(&(ctx.tuphdr)->t_ctid); - if (nextblkno == ctx.blkno && nextoffnum != ctx.offnum) + if (nextblkno == ctx.blkno && nextoffnum != ctx.offnum && + nextoffnum >= FirstOffsetNumber && nextoffnum <= maxoff) successor[ctx.offnum] = nextoffnum; } @@ -665,15 +666,18 @@ verify_heapam(PG_FUNCTION_ARGS) * tuple should be marked as a heap-only tuple. Conversely, if the * current tuple isn't marked as HOT-updated, then the next tuple * shouldn't be marked as a heap-only tuple. + * + * NB: Can't use HeapTupleHeaderIsHotUpdated() as it checks if + * hint bits indicate xmin/xmax aborted. */ - if (!HeapTupleHeaderIsHotUpdated(curr_htup) && + if (!(curr_htup->t_infomask2 & HEAP_HOT_UPDATED) && HeapTupleHeaderIsHeapOnly(next_htup)) { report_corruption(&ctx, psprintf("non-heap-only update produced a heap-only tuple at offset %u", (unsigned) nextoffnum)); } - if (HeapTupleHeaderIsHotUpdated(curr_htup) && + if ((curr_htup->t_infomask2 & HEAP_HOT_UPDATED) && !HeapTupleHeaderIsHeapOnly(next_htup)) { report_corruption(&ctx, -- 2.30.2