diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index 919138eaf3..90688376a6 100644
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -2330,12 +2330,14 @@ varstrfastcmp_locale(char *a1p, int len1, char *a2p, int len2, SortSupport ssup)
 
 	if (len1 >= sss->buflen1)
 	{
+		Assert(ssup->ssup_cxt == GetMemoryChunkContext(sss->buf1));
 		pfree(sss->buf1);
 		sss->buflen1 = Max(len1 + 1, Min(sss->buflen1 * 2, MaxAllocSize));
 		sss->buf1 = MemoryContextAlloc(ssup->ssup_cxt, sss->buflen1);
 	}
 	if (len2 >= sss->buflen2)
 	{
+		Assert(ssup->ssup_cxt == GetMemoryChunkContext(sss->buf2));
 		pfree(sss->buf2);
 		sss->buflen2 = Max(len2 + 1, Min(sss->buflen2 * 2, MaxAllocSize));
 		sss->buf2 = MemoryContextAlloc(ssup->ssup_cxt, sss->buflen2);
@@ -2518,9 +2520,10 @@ varstr_abbrev_convert(Datum original, SortSupport ssup)
 		/* By convention, we use buffer 1 to store and NUL-terminate */
 		if (len >= sss->buflen1)
 		{
+			Assert(ssup->ssup_cxt == GetMemoryChunkContext(sss->buf1));
 			pfree(sss->buf1);
 			sss->buflen1 = Max(len + 1, Min(sss->buflen1 * 2, MaxAllocSize));
-			sss->buf1 = palloc(sss->buflen1);
+			sss->buf1 = MemoryContextAlloc(ssup->ssup_cxt, sss->buflen1);
 		}
 
 		/* Might be able to reuse strxfrm() blob from last call */
@@ -2607,10 +2610,11 @@ varstr_abbrev_convert(Datum original, SortSupport ssup)
 			/*
 			 * Grow buffer and retry.
 			 */
+			Assert(ssup->ssup_cxt == GetMemoryChunkContext(sss->buf2));
 			pfree(sss->buf2);
 			sss->buflen2 = Max(bsize + 1,
 							   Min(sss->buflen2 * 2, MaxAllocSize));
-			sss->buf2 = palloc(sss->buflen2);
+			sss->buf2 = MemoryContextAlloc(ssup->ssup_cxt, sss->buflen2);
 		}
 
 		/*