diff --git a/tests/lib/libc/db/Makefile b/tests/lib/libc/db/Makefile
index 60a7764433db..ffcc96e98bf6 100644
--- a/tests/lib/libc/db/Makefile
+++ b/tests/lib/libc/db/Makefile
@@ -1,4 +1,4 @@
-# $NetBSD: Makefile,v 1.2 2015/06/22 19:06:05 christos Exp $
+# $NetBSD: Makefile,v 1.3 2015/11/18 18:35:35 christos Exp $
 
 .include <bsd.own.mk>
 
@@ -12,6 +12,7 @@ BINDIR=		${TESTSDIR}
 MKMAN=		no
 
 PROGS+=		h_db
+PROGS+=		h_lfsr
 
 FILESDIR=	${TESTSDIR}
 
diff --git a/tests/lib/libc/db/h_lfsr.c b/tests/lib/libc/db/h_lfsr.c
new file mode 100644
index 000000000000..3f3d712dfd85
--- /dev/null
+++ b/tests/lib/libc/db/h_lfsr.c
@@ -0,0 +1,179 @@
+/*-
+ * Copyright (c) 2015 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Christos Zoulas.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+#include <sys/cdefs.h>
+__RCSID("$NetBSD: h_lfsr.c,v 1.1 2015/11/18 18:35:35 christos Exp $");
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <err.h>
+#include <string.h>
+#include <unistd.h>
+#include <db.h>
+
+#define MAXKEY 0xffff
+#ifdef DEBUG
+#define DPRINTF(...)	printf(__VA_ARGS__)
+#else
+#define DPRINTF(...)
+#endif
+
+static uint16_t
+next(uint16_t *cur)
+{
+        uint16_t lsb = *cur & 1;
+        *cur >>= 1;
+        *cur ^= (-lsb) & 0xB400u;
+	return *cur;
+}
+
+int
+main(int argc, char *argv[])
+{
+	char buf[65536];
+	char kb[256];
+	DBT key, val;
+	DB *db;
+	HASHINFO hi;
+	uint8_t c;
+	uint16_t len;
+	uint32_t pagesize = atoi(argv[1]);
+
+	memset(&hi, 0, sizeof(hi));
+	memset(buf, 'a', sizeof(buf));
+	hi.bsize = pagesize;
+	hi.nelem = 65536;
+	hi.ffactor = 128;
+
+	key.data = kb;
+	val.data = buf;
+
+	db = dbopen(NULL, O_CREAT|O_TRUNC|O_RDWR, 0, DB_HASH, &hi);
+	if (db == NULL)
+		err(EXIT_FAILURE, "dbopen");
+
+	len = 0xaec1;
+	for (size_t i = 0; i < MAXKEY; i++) {
+		key.size = (len & 0xff) + 1;
+		c = len >> 8;
+		memset(kb, c, key.size);
+		val.size = (next(&len) & 0xff) + 1;
+		switch ((*db->put)(db, &key, &val, R_NOOVERWRITE)) {
+		case 0:
+			DPRINTF("put %zu %zu %#x\n",
+			    key.size, val.size, c);
+			break;
+		case -1:
+			err(EXIT_FAILURE, "put error %zu %zu %#x",
+			    key.size, val.size, c);
+		case 1:
+			errx(EXIT_FAILURE, "put overwrite %zu %zu %#x",
+			    key.size, val.size, c);
+		default:
+			abort();
+		}
+	}
+
+	len = 0xaec1;
+	for (size_t i = 0; i < MAXKEY; i++) {
+		key.size = (len & 0xff) + 1;
+		c = len >> 8;
+		memset(kb, c, key.size);
+		next(&len);
+		switch ((*db->get)(db, &key, &val, 0)) {
+		case 0:
+			DPRINTF("get %zu %zu %#x\n",
+			    key.size, val.size, c);
+			break;
+		case -1:
+			err(EXIT_FAILURE, "get %zu %zu %#x",
+			    key.size, val.size, c);
+		case 1:
+			errx(EXIT_FAILURE, "get not found %zu %zu %#x",
+			    key.size, val.size, c);
+		default:
+			abort();
+		}
+		if (memcmp(key.data, kb, key.size) != 0)
+			errx(EXIT_FAILURE, "get badkey %zu %zu %#x",
+			    key.size, val.size, c);
+		if (val.size != (len & 0xff) + 1U)
+			errx(EXIT_FAILURE, "get badvallen %zu %zu %#x",
+			    key.size, val.size, c);
+		if (memcmp(val.data, buf, val.size) != 0)
+			errx(EXIT_FAILURE, "get badval %zu %zu %#x",
+			    key.size, val.size, c);
+	}
+	
+	len = 0xaec1;
+	for (size_t i = 0; i < MAXKEY; i++) {
+		key.size = (len & 0xff) + 1;
+		c = len >> 8;
+		memset(kb, c, key.size);
+		next(&len);
+		switch ((*db->del)(db, &key, 0)) {
+		case 0:
+			DPRINTF("del %zu %zu %#x\n",
+			    key.size, val.size, c);
+			break;
+		case -1:
+			err(EXIT_FAILURE, "del %zu %zu %#x", key.size,
+			    val.size, c);
+		case 1:
+			errx(EXIT_FAILURE, "del not found %zu %zu %#x",
+			    key.size, val.size, c);
+		default:
+			abort();
+		}
+	}
+
+	len = 0xaec1;
+	for (size_t i = 0; i < MAXKEY; i++) {
+		key.size = (len & 0xff) + 1;
+		c = len >> 8;
+		memset(kb, c, key.size);
+		next(&len);
+		switch ((*db->get)(db, &key, &val, 0)) {
+		case 0:
+			errx(EXIT_FAILURE, "get2 found %zu %zu %#x",
+			    key.size, val.size, c);
+			break;
+		case -1:
+			err(EXIT_FAILURE, "get2 %zu %zu %#x",
+			    key.size, val.size, c);
+		case 1:
+			DPRINTF("get2 %zu %zu %#x\n",
+			    key.size, val.size, c);
+			break;
+		default:
+			abort();
+		}
+	}
+	return 0;
+}
diff --git a/tests/lib/libc/db/t_db.sh b/tests/lib/libc/db/t_db.sh
index a16843a0d94e..53500ffe4a05 100644
--- a/tests/lib/libc/db/t_db.sh
+++ b/tests/lib/libc/db/t_db.sh
@@ -1,4 +1,4 @@
-# $NetBSD: t_db.sh,v 1.5 2015/02/26 13:00:26 martin Exp $
+# $NetBSD: t_db.sh,v 1.6 2015/11/18 18:35:35 christos Exp $
 #
 # Copyright (c) 2008 The NetBSD Foundation, Inc.
 # All rights reserved.
@@ -25,11 +25,16 @@
 # POSSIBILITY OF SUCH DAMAGE.
 #
 
-prog()
+prog_db()
 {
 	echo $(atf_get_srcdir)/h_db
 }
 
+prog_lfsr()
+{
+	echo $(atf_get_srcdir)/h_lfsr
+}
+
 dict()
 {
 	if [ -f /usr/share/dict/words ]; then
@@ -66,7 +71,7 @@ small_btree_body()
 		echo k$i
 	done >in
 
-	atf_check -o file:exp "$(prog)" btree in
+	atf_check -o file:exp "$(prog_db)" btree in
 }
 
 atf_test_case small_hash
@@ -92,7 +97,7 @@ small_hash_body()
 		echo k$i
 	done >in
 
-	atf_check -o file:exp "$(prog)" hash in
+	atf_check -o file:exp "$(prog_db)" hash in
 }
 
 atf_test_case small_recno
@@ -116,7 +121,7 @@ small_recno_body()
 		printf("p\nk%d\nd%s\ng\nk%d\n", i, $0, i);
 	}' >in
 
-	atf_check -o file:exp "$(prog)" recno in
+	atf_check -o file:exp "$(prog_db)" recno in
 }
 
 atf_test_case medium_btree
@@ -144,7 +149,7 @@ medium_btree_body()
 		echo k$i
 	done >in
 
-	atf_check -o file:exp "$(prog)" btree in
+	atf_check -o file:exp "$(prog_db)" btree in
 }
 
 atf_test_case medium_hash
@@ -172,7 +177,7 @@ medium_hash_body()
 		echo k$i
 	done >in
 
-	atf_check -o file:exp "$(prog)" hash in
+	atf_check -o file:exp "$(prog_db)" hash in
 }
 
 atf_test_case medium_recno
@@ -197,7 +202,7 @@ medium_recno_body()
 		printf("p\nk%d\nd%s\ng\nk%d\n", i, $0, i);
 	}' >in
 
-	atf_check -o file:exp "$(prog)" recno in
+	atf_check -o file:exp "$(prog_db)" recno in
 }
 
 atf_test_case big_btree
@@ -226,7 +231,7 @@ big_btree_body()
 			echo k$i
 		done >in
 
-		atf_check "$(prog)" -o out btree in
+		atf_check "$(prog_db)" -o out btree in
 		cmp -s exp out || atf_fail "test failed for page size: $psize"
 	done
 }
@@ -254,7 +259,7 @@ big_hash_body()
 		echo k$i
 	done >in
 
-	atf_check "$(prog)" -o out hash in
+	atf_check "$(prog_db)" -o out hash in
 	cmp -s exp out || atf_fail "test failed"
 }
 
@@ -282,7 +287,7 @@ big_recno_body()
 	for psize in 512 16384 65536; do
 		echo "checking page size: $psize"
 
-		atf_check "$(prog)" -o out recno in
+		atf_check "$(prog_db)" -o out recno in
 		cmp -s exp out || atf_fail "test failed for page size: $psize"
 	done
 }
@@ -350,7 +355,7 @@ random_recno_body()
 				printf("g\nk%d\n", i);
 		}' >in
 
-	atf_check -o file:exp "$(prog)" recno in
+	atf_check -o file:exp "$(prog_db)" recno in
 }
 
 atf_test_case reverse_recno
@@ -388,7 +393,7 @@ reverse_recno_body()
 				printf("g\nk%d\n", i);
 		}' >in
 
-	atf_check -o file:exp "$(prog)" recno in
+	atf_check -o file:exp "$(prog_db)" recno in
 }
 		
 atf_test_case alternate_recno
@@ -440,7 +445,7 @@ alternate_recno_body()
 				printf("g\nk%d\n", i);
 		}' >in
 
-	atf_check "$(prog)" -o out recno in
+	atf_check "$(prog_db)" -o out recno in
 	
 	sort -o exp exp
 	sort -o out out
@@ -509,7 +514,7 @@ h_delete()
 		}' >> exp
 	fi
 
-	atf_check "$(prog)" -o out $type in
+	atf_check "$(prog_db)" -o out $type in
 	atf_check -o file:exp cat out
 }
 
@@ -553,7 +558,7 @@ h_repeated()
 		}
 	}' >in
 
-	$(prog) btree in
+	$(prog_db) btree in
 }
 
 atf_test_case repeated_btree
@@ -608,7 +613,7 @@ duplicate_btree_body()
 			printf("o\n");
 	}' >in
 
-	atf_check -o file:exp -x "$(prog) -iflags=1 btree in | sort"
+	atf_check -o file:exp -x "$(prog_db) -iflags=1 btree in | sort"
 }
 
 h_cursor_flags()
@@ -637,7 +642,7 @@ h_cursor_flags()
 		printf("eR_CURSOR SHOULD HAVE FAILED\n");
 	}' >in
 
-	atf_check -o ignore -e ignore -s ne:0 "$(prog)" -o out $type in
+	atf_check -o ignore -e ignore -s ne:0 "$(prog_db)" -o out $type in
 	atf_check -s ne:0 test -s out
 
 	cat exp |
@@ -651,7 +656,7 @@ h_cursor_flags()
 		printf("eR_CURSOR SHOULD HAVE FAILED\n");
 	}' >in
 
-	atf_check -o ignore -e ignore -s ne:0 "$(prog)" -o out $type in
+	atf_check -o ignore -e ignore -s ne:0 "$(prog_db)" -o out $type in
 	atf_check -s ne:0 test -s out
 }
 
@@ -707,7 +712,7 @@ reverse_order_recno_body()
 			printf("or\n");
 	}' >in
 
-	atf_check -o file:exp "$(prog)" recno in
+	atf_check -o file:exp "$(prog_db)" recno in
 }
 
 atf_test_case small_page_btree
@@ -737,7 +742,7 @@ small_page_btree_body()
 		echo k$i
 	done >in
 
-	atf_check -o file:exp "$(prog)" -i psize=512 btree in
+	atf_check -o file:exp "$(prog_db)" -i psize=512 btree in
 }
 
 h_byte_orders()
@@ -757,14 +762,14 @@ h_byte_orders()
 			echo k$i
 		done >in
 
-		atf_check -o file:exp "$(prog)" -ilorder=$order -f byte.file $type in
+		atf_check -o file:exp "$(prog_db)" -ilorder=$order -f byte.file $type in
 
 		for i in `sed 50q $(dict)`; do
 			echo g
 			echo k$i
 		done >in
 
-		atf_check -o file:exp "$(prog)" -s -ilorder=$order -f byte.file $type in
+		atf_check -o file:exp "$(prog_db)" -s -ilorder=$order -f byte.file $type in
 	done
 }
 
@@ -794,7 +799,7 @@ h_bsize_ffactor()
 	ffactor=$2
 
 	echo "bucketsize $bsize, fill factor $ffactor"
-	atf_check -o file:exp "$(prog)" "-ibsize=$bsize,\
+	atf_check -o file:exp "$(prog_db)" "-ibsize=$bsize,\
 ffactor=$ffactor,nelem=25000,cachesize=65536" hash in
 }
 
@@ -864,9 +869,21 @@ bsize_ffactor_body()
 	h_bsize_ffactor 8192 341
 	h_bsize_ffactor 8192 455
 	h_bsize_ffactor 8192 683
+
+	h_bsize_ffactor 16384 341
+	h_bsize_ffactor 16384 455
+	h_bsize_ffactor 16384 683
+
+	h_bsize_ffactor 32768 341
+	h_bsize_ffactor 32768 455
+	h_bsize_ffactor 32768 683
+
+	h_bsize_ffactor 65536 341
+	h_bsize_ffactor 65536 455
+	h_bsize_ffactor 65536 683
 }
 
-# FIXME: what does it test?
+# This tests 64K block size addition/removal
 atf_test_case four_char_hash
 four_char_hash_head()
 {
@@ -887,7 +904,24 @@ r
 k1234
 EOF
 
-	atf_check "$(prog)" -i bsize=65536 hash in
+	atf_check "$(prog_db)" -i bsize=65536 hash in
+}
+
+
+atf_test_case bsize_torture
+bsize_torture_head()
+{
+	atf_set "timeout" "36000"
+	atf_set "descr" "Checks hash database with various bucket sizes"
+}
+bsize_torture_body()
+{
+	TMPDIR="$(pwd)/db_dir"; export TMPDIR
+	mkdir ${TMPDIR}
+	for i in 2048 4096 8192 16384 32768 65536
+	do
+		atf_check "$(prog_lfsr)" $i
+	done
 }
 
 atf_init_test_cases()
@@ -917,4 +951,5 @@ atf_init_test_cases()
 	atf_add_test_case byte_orders_hash
 	atf_add_test_case bsize_ffactor
 	atf_add_test_case four_char_hash
+	atf_add_test_case bsize_torture
 }