lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [day] [month] [year] [list]
Date:   Fri, 21 Oct 2022 15:45:23 +0200
From:   Rolf Eike Beer <eike@...mail.de>
To:     Thomas Graf <tgraf@...g.ch>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        Florian Westphal <fw@...len.de>
Cc:     netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        "Jason A. Donenfeld" <Jason@...c4.com>
Subject: [PATCH] rhashtable: make test actually random

The "random rhlist add/delete operations" actually wasn't very random, as all
cases tested the same bit. Since the later parts of this loop depend on the
first case execute this unconditionally, and then test on different bits for the
remaining tests. While at it only request as much random bits as are actually
used.

Signed-off-by: Rolf Eike Beer <eike-kernel@...tec.de>
---
 lib/test_rhashtable.c | 58 ++++++++++++++++---------------------------
 1 file changed, 22 insertions(+), 36 deletions(-)

diff --git a/lib/test_rhashtable.c b/lib/test_rhashtable.c
index b358a74ed7ed..f2ba5787055a 100644
--- a/lib/test_rhashtable.c
+++ b/lib/test_rhashtable.c
@@ -369,18 +369,10 @@ static int __init test_rhltable(unsigned int entries)
 	pr_info("test %d random rhlist add/delete operations\n", entries);
 	for (j = 0; j < entries; j++) {
 		u32 i = prandom_u32_max(entries);
-		u32 prand = get_random_u32();
+		u32 prand = prandom_u32_max(4);
 
 		cond_resched();
 
-		if (prand == 0)
-			prand = get_random_u32();
-
-		if (prand & 1) {
-			prand >>= 1;
-			continue;
-		}
-
 		err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
 		if (test_bit(i, obj_in_table)) {
 			clear_bit(i, obj_in_table);
@@ -393,35 +385,29 @@ static int __init test_rhltable(unsigned int entries)
 		}
 
 		if (prand & 1) {
-			prand >>= 1;
-			continue;
-		}
-
-		err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
-		if (err == 0) {
-			if (WARN(test_and_set_bit(i, obj_in_table), "succeeded to insert same object %d", i))
-				continue;
-		} else {
-			if (WARN(!test_bit(i, obj_in_table), "failed to insert object %d", i))
-				continue;
-		}
-
-		if (prand & 1) {
-			prand >>= 1;
-			continue;
+			err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
+			if (err == 0) {
+				if (WARN(test_and_set_bit(i, obj_in_table), "succeeded to insert same object %d", i))
+					continue;
+			} else {
+				if (WARN(!test_bit(i, obj_in_table), "failed to insert object %d", i))
+					continue;
+			}
 		}
 
-		i = prandom_u32_max(entries);
-		if (test_bit(i, obj_in_table)) {
-			err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
-			WARN(err, "cannot remove element at slot %d", i);
-			if (err == 0)
-				clear_bit(i, obj_in_table);
-		} else {
-			err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
-			WARN(err, "failed to insert object %d", i);
-			if (err == 0)
-				set_bit(i, obj_in_table);
+		if (prand & 2) {
+			i = prandom_u32_max(entries);
+			if (test_bit(i, obj_in_table)) {
+				err = rhltable_remove(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
+				WARN(err, "cannot remove element at slot %d", i);
+				if (err == 0)
+					clear_bit(i, obj_in_table);
+			} else {
+				err = rhltable_insert(&rhlt, &rhl_test_objects[i].list_node, test_rht_params);
+				WARN(err, "failed to insert object %d", i);
+				if (err == 0)
+					set_bit(i, obj_in_table);
+			}
 		}
 	}
 
-- 
2.35.3




Powered by blists - more mailing lists