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From: Feng Jiang <jiangfeng@kylinos.cn>
To: pjw@kernel.org, palmer@dabbelt.com, aou@eecs.berkeley.edu,
	alex@ghiti.fr, akpm@linux-foundation.org, kees@kernel.org,
	andy@kernel.org, jiangfeng@kylinos.cn, ebiggers@kernel.org,
	martin.petersen@oracle.com, sohil.mehta@intel.com,
	charlie@rivosinc.com, conor.dooley@microchip.com,
	samuel.holland@sifive.com, linus.walleij@linaro.org,
	nathan@kernel.org
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux-hardening@vger.kernel.org, Joel Stanley <joel@jms.id.au>
Subject: [PATCH v5 3/8] lib/string_kunit: add correctness test for strrchr()
Date: Tue, 27 Jan 2026 09:25:53 +0800	[thread overview]
Message-ID: <20260127012558.40025-4-jiangfeng@kylinos.cn> (raw)
In-Reply-To: <20260127012558.40025-1-jiangfeng@kylinos.cn>

Introduce a KUnit test to verify strrchr() across various memory
alignments and character positions. This ensures the implementation
correctly identifies the last occurrence of a character.

Signed-off-by: Feng Jiang <jiangfeng@kylinos.cn>
Acked-by: Andy Shevchenko <andy@kernel.org>
Tested-by: Joel Stanley <joel@jms.id.au>
---
 lib/tests/string_kunit.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/lib/tests/string_kunit.c b/lib/tests/string_kunit.c
index 991f01d52eb2..7f1e2bf6a352 100644
--- a/lib/tests/string_kunit.c
+++ b/lib/tests/string_kunit.c
@@ -184,6 +184,35 @@ static void string_test_strchr(struct kunit *test)
 	KUNIT_ASSERT_NULL(test, result);
 }
 
+static void string_test_strrchr(struct kunit *test)
+{
+	const size_t buf_size = STRING_TEST_MAX_LEN + STRING_TEST_MAX_OFFSET + 1;
+	size_t offset, len;
+	char *buf;
+
+	buf = kunit_kzalloc(test, buf_size, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, buf);
+
+	memset(buf, 'A', buf_size);
+	buf[buf_size - 1] = '\0';
+
+	for (offset = 0; offset < STRING_TEST_MAX_OFFSET; offset++) {
+		for (len = 0; len <= STRING_TEST_MAX_LEN; len++) {
+			buf[offset + len] = '\0';
+
+			KUNIT_EXPECT_PTR_EQ(test, strrchr(buf + offset, 'Z'), NULL);
+
+			if (len > 0)
+				KUNIT_EXPECT_PTR_EQ(test, strrchr(buf + offset, 'A'),
+						buf + offset + len - 1);
+			else
+				KUNIT_EXPECT_PTR_EQ(test, strrchr(buf + offset, 'A'), NULL);
+
+			buf[offset + len] = 'A';
+		}
+	}
+}
+
 static void string_test_strnchr(struct kunit *test)
 {
 	const char *test_string = "abcdefghijkl";
@@ -679,6 +708,7 @@ static struct kunit_case string_test_cases[] = {
 	KUNIT_CASE(string_test_strnlen),
 	KUNIT_CASE(string_test_strchr),
 	KUNIT_CASE(string_test_strnchr),
+	KUNIT_CASE(string_test_strrchr),
 	KUNIT_CASE(string_test_strspn),
 	KUNIT_CASE(string_test_strcmp),
 	KUNIT_CASE(string_test_strcmp_long_strings),
-- 
2.25.1


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  parent reply	other threads:[~2026-01-27  1:26 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-01-27  1:25 [PATCH v5 0/8] riscv: optimize string functions and add kunit tests Feng Jiang
2026-01-27  1:25 ` [PATCH v5 1/8] lib/string_kunit: add correctness test for strlen() Feng Jiang
2026-01-28 22:39   ` Kees Cook
2026-01-29  2:19     ` Feng Jiang
2026-01-27  1:25 ` [PATCH v5 2/8] lib/string_kunit: add correctness test for strnlen() Feng Jiang
2026-01-27  1:25 ` Feng Jiang [this message]
2026-01-27  1:25 ` [PATCH v5 4/8] lib/string_kunit: add performance benchmark for strlen() Feng Jiang
2026-01-27  8:57   ` Andy Shevchenko
2026-01-27  9:33     ` Feng Jiang
2026-01-27  9:50       ` Andy Shevchenko
2026-01-28  1:44         ` Feng Jiang
2026-01-28  8:59           ` Andy Shevchenko
2026-01-28  9:20             ` Feng Jiang
2026-01-27  1:25 ` [PATCH v5 5/8] lib/string_kunit: extend benchmarks to strnlen() and chr searches Feng Jiang
2026-01-27  1:25 ` [PATCH v5 6/8] riscv: lib: add strnlen() implementation Feng Jiang
2026-01-27  1:25 ` [PATCH v5 7/8] riscv: lib: add strchr() implementation Feng Jiang
2026-01-27  1:25 ` [PATCH v5 8/8] riscv: lib: add strrchr() implementation Feng Jiang

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