[PATCH v7 3/6] lib/string_kunit: Add test for copy_task_comm()
From: André Almeida <andrealmeid@igalia.com>
Date: 2026-09-12 01:24:39
Also in:
linux-mm, linux-trace-kernel, lkml
Subsystem:
generic string library, library code, the rest · Maintainers:
Kees Cook, Andrew Morton, Linus Torvalds
Add a new test for copy_task_comm(). Check if a copy from a task_struct works, and special cases when the size of source and destination buffer mismatches. Signed-off-by: André Almeida <andrealmeid@igalia.com> --- lib/tests/string_kunit.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+)
diff --git a/lib/tests/string_kunit.c b/lib/tests/string_kunit.c
index 0819ace5b027..66c3398f2317 100644
--- a/lib/tests/string_kunit.c
+++ b/lib/tests/string_kunit.c@@ -881,6 +881,43 @@ static void string_bench_strrchr(struct kunit *test) STRING_BENCH_BUF(test, buf, len, strrchr, buf, '\0'); } +#define TASK_NAME "task_name" +#define TASK_NAME_LEN 9 +#define TASK_MAX_LEN TASK_COMM_LEN +#define SMALLER_LEN (TASK_NAME_LEN - 3) +#define BIGGER_LEN (TASK_MAX_LEN + 3) + +static void string_copy_task_comm(struct kunit *test) +{ + char str[TASK_MAX_LEN] = TASK_NAME, copy[TASK_MAX_LEN], + smaller_buf[SMALLER_LEN], bigger_buf[BIGGER_LEN]; + static struct task_struct task, *tsk = &task; + int len1, len2, i; + + /* set and get task name */ + strscpy_pad(tsk->comm, str); + copy_task_comm(copy, tsk, TASK_COMM_LEN); + + len1 = strlen(str); + len2 = strlen(copy); + + KUNIT_ASSERT_EQ(test, len1, len2); + KUNIT_ASSERT_EQ(test, len2, TASK_NAME_LEN); + KUNIT_ASSERT_EQ(test, copy[len2], '\0'); + KUNIT_ASSERT_TRUE(test, !strcmp(str, copy)); + + /* copy to a smaller dst buffer */ + copy_task_comm(smaller_buf, tsk, sizeof(smaller_buf)); + KUNIT_ASSERT_TRUE(test, !strncmp(str, smaller_buf, SMALLER_LEN - 1)); + KUNIT_ASSERT_EQ(test, smaller_buf[SMALLER_LEN - 1], '\0'); + + /* copy to a bigger dst buffer */ + copy_task_comm(bigger_buf, tsk, sizeof(bigger_buf)); + KUNIT_ASSERT_TRUE(test, !strncmp(str, bigger_buf, TASK_NAME_LEN)); + for (i = TASK_NAME_LEN; i < BIGGER_LEN; i++) + KUNIT_ASSERT_EQ(test, bigger_buf[i], '\0'); +} + static struct kunit_case string_test_cases[] = { KUNIT_CASE(string_test_memset16), KUNIT_CASE(string_test_memset32),
@@ -910,6 +947,7 @@ static struct kunit_case string_test_cases[] = { KUNIT_CASE(string_bench_strnlen), KUNIT_CASE(string_bench_strchr), KUNIT_CASE(string_bench_strrchr), + KUNIT_CASE(string_copy_task_comm), {} };
--
2.55.0