1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2023 Cyril Hrubis <[email protected]>
4 */
5
6 /*\
7 * [Description]
8 *
9 * Sanity tests for the /proc/sys/kernel/sched_r* files.
10 *
11 * - The sched_rt_period_us range is 1 to INT_MAX
12 * try invalid values and check for EINVAL
13 *
14 * - The sched_rt_runtime_us range is -1 to INT_MAX
15 * try invalid values and check for EINVAL
16 *
17 * - The sched_rt_runtime_us must be less or equal to sched_rt_period_us
18 *
19 * - Reset sched_rr_timeslice_ms to default value by writing -1 and check that
20 * we get the default value on next read.
21 *
22 * This is a regression test for a commits:
23 *
24 * - c1fc6484e1fb ("sched/rt: sysctl_sched_rr_timeslice show default timeslice after reset")
25 * - 079be8fc6309 ("sched/rt: Disallow writing invalid values to sched_rt_period_us")
26 */
27
28 #include <stdio.h>
29 #include "tst_test.h"
30
31 #define RT_PERIOD_US "/proc/sys/kernel/sched_rt_period_us"
32 #define RT_RUNTIME_US "/proc/sys/kernel/sched_rt_runtime_us"
33 #define RR_TIMESLICE_MS "/proc/sys/kernel/sched_rr_timeslice_ms"
34
35 static int period_fd;
36 static int runtime_fd;
37
rr_timeslice_ms_reset(void)38 static void rr_timeslice_ms_reset(void)
39 {
40 long timeslice_ms;
41
42 SAFE_FILE_PRINTF(RR_TIMESLICE_MS, "-1");
43 SAFE_FILE_SCANF(RR_TIMESLICE_MS, "%li", ×lice_ms);
44
45 TST_EXP_EXPR(timeslice_ms > 0,
46 "timeslice_ms > 0 after reset to default");
47 }
48
rt_period_us_einval(void)49 static void rt_period_us_einval(void)
50 {
51 TST_EXP_FAIL(write(period_fd, "0", 2), EINVAL,
52 "echo 0 > "RT_PERIOD_US);
53 TST_EXP_FAIL(write(period_fd, "-1", 2), EINVAL,
54 "echo -1 > "RT_PERIOD_US);
55 }
56
rt_runtime_us_einval(void)57 static void rt_runtime_us_einval(void)
58 {
59 TST_EXP_FAIL(write(runtime_fd, "-2", 2), EINVAL,
60 "echo -2 > "RT_RUNTIME_US);
61 }
62
rt_runtime_us_le_period_us(void)63 static void rt_runtime_us_le_period_us(void)
64 {
65 int period_us;
66 char buf[32];
67
68 SAFE_FILE_SCANF(RT_PERIOD_US, "%i", &period_us);
69
70 sprintf(buf, "%i", period_us+1);
71
72 TST_EXP_FAIL(write(runtime_fd, buf, strlen(buf)), EINVAL,
73 "echo rt_period_us+1 > "RT_RUNTIME_US);
74 }
75
verify_sched_proc(void)76 static void verify_sched_proc(void)
77 {
78 rr_timeslice_ms_reset();
79 rt_period_us_einval();
80 rt_runtime_us_einval();
81 rt_runtime_us_le_period_us();
82 }
83
setup(void)84 static void setup(void)
85 {
86 period_fd = open(RT_PERIOD_US, O_RDWR);
87 runtime_fd = open(RT_RUNTIME_US, O_RDWR);
88 }
89
cleanup(void)90 static void cleanup(void)
91 {
92 if (period_fd > 0)
93 SAFE_CLOSE(period_fd);
94
95 if (runtime_fd > 0)
96 SAFE_CLOSE(runtime_fd);
97 }
98
99 static struct tst_test test = {
100 .needs_root = 1,
101 .setup = setup,
102 .cleanup = cleanup,
103 .test_all = verify_sched_proc,
104 .tags = (struct tst_tag []) {
105 {"linux-git", "c1fc6484e1fb"},
106 {"linux-git", "079be8fc6309"},
107 {}
108 },
109 .needs_kconfigs = (const char *[]) {
110 "CONFIG_SYSCTL",
111 NULL
112 },
113 };
114