From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- lib/tests/hashtable_test.c | 318 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 318 insertions(+) create mode 100644 lib/tests/hashtable_test.c (limited to 'lib/tests/hashtable_test.c') diff --git a/lib/tests/hashtable_test.c b/lib/tests/hashtable_test.c new file mode 100644 index 000000000..3521de6ba --- /dev/null +++ b/lib/tests/hashtable_test.c @@ -0,0 +1,318 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KUnit test for the Kernel Hashtable structures. + * + * Copyright (C) 2022, Google LLC. + * Author: Rae Moar + */ +#include + +#include + +struct hashtable_test_entry { + int key; + int data; + struct hlist_node node; + int visited; +}; + +static void hashtable_test_hash_init(struct kunit *test) +{ + /* Test the different ways of initialising a hashtable. */ + DEFINE_HASHTABLE(hash1, 2); + DECLARE_HASHTABLE(hash2, 3); + + /* When using DECLARE_HASHTABLE, must use hash_init to + * initialize the hashtable. + */ + hash_init(hash2); + + KUNIT_EXPECT_TRUE(test, hash_empty(hash1)); + KUNIT_EXPECT_TRUE(test, hash_empty(hash2)); +} + +static void hashtable_test_hash_empty(struct kunit *test) +{ + struct hashtable_test_entry a; + DEFINE_HASHTABLE(hash, 1); + + KUNIT_EXPECT_TRUE(test, hash_empty(hash)); + + a.key = 1; + a.data = 13; + hash_add(hash, &a.node, a.key); + + /* Hashtable should no longer be empty. */ + KUNIT_EXPECT_FALSE(test, hash_empty(hash)); +} + +static void hashtable_test_hash_hashed(struct kunit *test) +{ + struct hashtable_test_entry a, b; + DEFINE_HASHTABLE(hash, 4); + + a.key = 1; + a.data = 13; + hash_add(hash, &a.node, a.key); + b.key = 1; + b.data = 2; + hash_add(hash, &b.node, b.key); + + KUNIT_EXPECT_TRUE(test, hash_hashed(&a.node)); + KUNIT_EXPECT_TRUE(test, hash_hashed(&b.node)); +} + +static void hashtable_test_hash_add(struct kunit *test) +{ + struct hashtable_test_entry a, b, *x; + int bkt; + DEFINE_HASHTABLE(hash, 3); + + a.key = 1; + a.data = 13; + a.visited = 0; + hash_add(hash, &a.node, a.key); + b.key = 2; + b.data = 10; + b.visited = 0; + hash_add(hash, &b.node, b.key); + + hash_for_each(hash, bkt, x, node) { + x->visited++; + if (x->key == a.key) + KUNIT_EXPECT_EQ(test, x->data, 13); + else if (x->key == b.key) + KUNIT_EXPECT_EQ(test, x->data, 10); + else + KUNIT_FAIL(test, "Unexpected key in hashtable."); + } + + /* Both entries should have been visited exactly once. */ + KUNIT_EXPECT_EQ(test, a.visited, 1); + KUNIT_EXPECT_EQ(test, b.visited, 1); +} + +static void hashtable_test_hash_del(struct kunit *test) +{ + struct hashtable_test_entry a, b, *x; + DEFINE_HASHTABLE(hash, 6); + + a.key = 1; + a.data = 13; + hash_add(hash, &a.node, a.key); + b.key = 2; + b.data = 10; + b.visited = 0; + hash_add(hash, &b.node, b.key); + + hash_del(&b.node); + hash_for_each_possible(hash, x, node, b.key) { + x->visited++; + KUNIT_EXPECT_NE(test, x->key, b.key); + } + + /* The deleted entry should not have been visited. */ + KUNIT_EXPECT_EQ(test, b.visited, 0); + + hash_del(&a.node); + + /* The hashtable should be empty. */ + KUNIT_EXPECT_TRUE(test, hash_empty(hash)); +} + +static void hashtable_test_hash_for_each(struct kunit *test) +{ + struct hashtable_test_entry entries[3]; + struct hashtable_test_entry *x; + int bkt, i, j, count; + DEFINE_HASHTABLE(hash, 3); + + /* Add three entries to the hashtable. */ + for (i = 0; i < 3; i++) { + entries[i].key = i; + entries[i].data = i + 10; + entries[i].visited = 0; + hash_add(hash, &entries[i].node, entries[i].key); + } + + count = 0; + hash_for_each(hash, bkt, x, node) { + x->visited += 1; + KUNIT_ASSERT_GE_MSG(test, x->key, 0, "Unexpected key in hashtable."); + KUNIT_ASSERT_LT_MSG(test, x->key, 3, "Unexpected key in hashtable."); + count++; + } + + /* Should have visited each entry exactly once. */ + KUNIT_EXPECT_EQ(test, count, 3); + for (j = 0; j < 3; j++) + KUNIT_EXPECT_EQ(test, entries[j].visited, 1); +} + +static void hashtable_test_hash_for_each_safe(struct kunit *test) +{ + struct hashtable_test_entry entries[3]; + struct hashtable_test_entry *x; + struct hlist_node *tmp; + int bkt, i, j, count; + DEFINE_HASHTABLE(hash, 3); + + /* Add three entries to the hashtable. */ + for (i = 0; i < 3; i++) { + entries[i].key = i; + entries[i].data = i + 10; + entries[i].visited = 0; + hash_add(hash, &entries[i].node, entries[i].key); + } + + count = 0; + hash_for_each_safe(hash, bkt, tmp, x, node) { + x->visited += 1; + KUNIT_ASSERT_GE_MSG(test, x->key, 0, "Unexpected key in hashtable."); + KUNIT_ASSERT_LT_MSG(test, x->key, 3, "Unexpected key in hashtable."); + count++; + + /* Delete entry during loop. */ + hash_del(&x->node); + } + + /* Should have visited each entry exactly once. */ + KUNIT_EXPECT_EQ(test, count, 3); + for (j = 0; j < 3; j++) + KUNIT_EXPECT_EQ(test, entries[j].visited, 1); +} + +static void hashtable_test_hash_for_each_possible(struct kunit *test) +{ + struct hashtable_test_entry entries[4]; + struct hashtable_test_entry *x, *y; + int buckets[2]; + int bkt, i, j, count; + DEFINE_HASHTABLE(hash, 5); + + /* Add three entries with key = 0 to the hashtable. */ + for (i = 0; i < 3; i++) { + entries[i].key = 0; + entries[i].data = i; + entries[i].visited = 0; + hash_add(hash, &entries[i].node, entries[i].key); + } + + /* Add an entry with key = 1. */ + entries[3].key = 1; + entries[3].data = 3; + entries[3].visited = 0; + hash_add(hash, &entries[3].node, entries[3].key); + + count = 0; + hash_for_each_possible(hash, x, node, 0) { + x->visited += 1; + KUNIT_ASSERT_GE_MSG(test, x->data, 0, "Unexpected data in hashtable."); + KUNIT_ASSERT_LT_MSG(test, x->data, 4, "Unexpected data in hashtable."); + count++; + } + + /* Should have visited each entry with key = 0 exactly once. */ + for (j = 0; j < 3; j++) + KUNIT_EXPECT_EQ(test, entries[j].visited, 1); + + /* Save the buckets for the different keys. */ + hash_for_each(hash, bkt, y, node) { + KUNIT_ASSERT_GE_MSG(test, y->key, 0, "Unexpected key in hashtable."); + KUNIT_ASSERT_LE_MSG(test, y->key, 1, "Unexpected key in hashtable."); + buckets[y->key] = bkt; + } + + /* If entry with key = 1 is in the same bucket as the entries with + * key = 0, check it was visited. Otherwise ensure that only three + * entries were visited. + */ + if (buckets[0] == buckets[1]) { + KUNIT_EXPECT_EQ(test, count, 4); + KUNIT_EXPECT_EQ(test, entries[3].visited, 1); + } else { + KUNIT_EXPECT_EQ(test, count, 3); + KUNIT_EXPECT_EQ(test, entries[3].visited, 0); + } +} + +static void hashtable_test_hash_for_each_possible_safe(struct kunit *test) +{ + struct hashtable_test_entry entries[4]; + struct hashtable_test_entry *x, *y; + struct hlist_node *tmp; + int buckets[2]; + int bkt, i, j, count; + DEFINE_HASHTABLE(hash, 5); + + /* Add three entries with key = 0 to the hashtable. */ + for (i = 0; i < 3; i++) { + entries[i].key = 0; + entries[i].data = i; + entries[i].visited = 0; + hash_add(hash, &entries[i].node, entries[i].key); + } + + /* Add an entry with key = 1. */ + entries[3].key = 1; + entries[3].data = 3; + entries[3].visited = 0; + hash_add(hash, &entries[3].node, entries[3].key); + + count = 0; + hash_for_each_possible_safe(hash, x, tmp, node, 0) { + x->visited += 1; + KUNIT_ASSERT_GE_MSG(test, x->data, 0, "Unexpected data in hashtable."); + KUNIT_ASSERT_LT_MSG(test, x->data, 4, "Unexpected data in hashtable."); + count++; + + /* Delete entry during loop. */ + hash_del(&x->node); + } + + /* Should have visited each entry with key = 0 exactly once. */ + for (j = 0; j < 3; j++) + KUNIT_EXPECT_EQ(test, entries[j].visited, 1); + + /* Save the buckets for the different keys. */ + hash_for_each(hash, bkt, y, node) { + KUNIT_ASSERT_GE_MSG(test, y->key, 0, "Unexpected key in hashtable."); + KUNIT_ASSERT_LE_MSG(test, y->key, 1, "Unexpected key in hashtable."); + buckets[y->key] = bkt; + } + + /* If entry with key = 1 is in the same bucket as the entries with + * key = 0, check it was visited. Otherwise ensure that only three + * entries were visited. + */ + if (buckets[0] == buckets[1]) { + KUNIT_EXPECT_EQ(test, count, 4); + KUNIT_EXPECT_EQ(test, entries[3].visited, 1); + } else { + KUNIT_EXPECT_EQ(test, count, 3); + KUNIT_EXPECT_EQ(test, entries[3].visited, 0); + } +} + +static struct kunit_case hashtable_test_cases[] = { + KUNIT_CASE(hashtable_test_hash_init), + KUNIT_CASE(hashtable_test_hash_empty), + KUNIT_CASE(hashtable_test_hash_hashed), + KUNIT_CASE(hashtable_test_hash_add), + KUNIT_CASE(hashtable_test_hash_del), + KUNIT_CASE(hashtable_test_hash_for_each), + KUNIT_CASE(hashtable_test_hash_for_each_safe), + KUNIT_CASE(hashtable_test_hash_for_each_possible), + KUNIT_CASE(hashtable_test_hash_for_each_possible_safe), + {}, +}; + +static struct kunit_suite hashtable_test_module = { + .name = "hashtable", + .test_cases = hashtable_test_cases, +}; + +kunit_test_suites(&hashtable_test_module); + +MODULE_DESCRIPTION("KUnit test for the Kernel Hashtable structures"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1