[PATCH 6/6] selftests: prctl: Add test for long thread names
From: André Almeida <andrealmeid@igalia.com>
Date: 2026-05-17 18:37:31
Also in:
linux-mm, lkml
Subsystem:
kernel selftest framework, the rest · Maintainers:
Shuah Khan, Linus Torvalds
Add tests for the new interface to set and get long thread names. The kernel should accept the LONG_NAME and returning it accordingly. For the old PR_GET_NAME interface, the kernel should truncate the name up to 16 chars. /proc/<task>/comm should return the same string ad PR_GET_NAME. Signed-off-by: André Almeida <andrealmeid@igalia.com> --- tools/testing/selftests/prctl/set-process-name.c | 36 ++++++++++++++++++++++++ 1 file changed, 36 insertions(+)
diff --git a/tools/testing/selftests/prctl/set-process-name.c b/tools/testing/selftests/prctl/set-process-name.c
index 3f7b146d36df..0f20f7deac67 100644
--- a/tools/testing/selftests/prctl/set-process-name.c
+++ b/tools/testing/selftests/prctl/set-process-name.c@@ -9,9 +9,17 @@ #include "kselftest_harness.h" +#ifndef PR_SET_EXT_NAME +# define PR_SET_EXT_NAME 17 +# define PR_GET_EXT_NAME 18 +#endif + #define CHANGE_NAME "changename" +#define LONG_NAME "change_to_very_long_extended_name" +#define LONG_NAME_CAP "change_to_very_" #define EMPTY_NAME "" #define TASK_COMM_LEN 16 +#define TASK_COMM_EXT_LEN 64 #define MAX_PATH_LEN 50 int set_name(char *name)
@@ -25,6 +33,16 @@ int set_name(char *name) return res; } +int set_ext_name(char *name) +{ + int res; + + res = prctl(PR_SET_EXT_NAME, name, NULL, NULL, NULL); + + if (res < 0) + return -errno; +} + int check_is_name_correct(char *check_name) { char name[TASK_COMM_LEN];
@@ -38,6 +56,19 @@ int check_is_name_correct(char *check_name) return !strcmp(name, check_name); } +int check_is_ext_name_correct(char *check_name) +{ + char name[TASK_COMM_EXT_LEN]; + int res; + + res = prctl(PR_GET_EXT_NAME, name, NULL, NULL, NULL); + + if (res < 0) + return -errno; + + return !strcmp(name, check_name); +} + int check_null_pointer(char *check_name) { char *name = NULL;
@@ -82,6 +113,11 @@ TEST(rename_process) { EXPECT_GE(set_name(CHANGE_NAME), 0); EXPECT_TRUE(check_is_name_correct(CHANGE_NAME)); + EXPECT_GE(set_ext_name(LONG_NAME), 0); + EXPECT_TRUE(check_is_ext_name_correct(LONG_NAME)); + EXPECT_TRUE(check_is_name_correct(LONG_NAME_CAP)); + EXPECT_TRUE(check_name()); + EXPECT_GE(set_name(EMPTY_NAME), 0); EXPECT_TRUE(check_is_name_correct(EMPTY_NAME));
--
2.54.0