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Subject[RFC PATCH v2 3/3] selftests: cgroup: Add basic tests for pids controller
Date
This commit adds (and wires in) new test program for checking basic pids
controller functionality -- restricting tasks in a cgroup and correct
event counting.

Signed-off-by: Michal Koutný <mkoutny@suse.com>
---
tools/testing/selftests/cgroup/Makefile | 8 +-
tools/testing/selftests/cgroup/test_pids.c | 188 +++++++++++++++++++++
2 files changed, 193 insertions(+), 3 deletions(-)
create mode 100644 tools/testing/selftests/cgroup/test_pids.c

diff --git a/tools/testing/selftests/cgroup/Makefile b/tools/testing/selftests/cgroup/Makefile
index 66aafe1f5746..15a8578f40b4 100644
--- a/tools/testing/selftests/cgroup/Makefile
+++ b/tools/testing/selftests/cgroup/Makefile
@@ -5,12 +5,14 @@ all:

TEST_FILES := with_stress.sh
TEST_PROGS := test_stress.sh
-TEST_GEN_PROGS = test_memcontrol
-TEST_GEN_PROGS += test_core
+TEST_GEN_PROGS = test_core
TEST_GEN_PROGS += test_freezer
+TEST_GEN_PROGS += test_memcontrol
+TEST_GEN_PROGS += test_pids

include ../lib.mk

-$(OUTPUT)/test_memcontrol: cgroup_util.c
$(OUTPUT)/test_core: cgroup_util.c
$(OUTPUT)/test_freezer: cgroup_util.c
+$(OUTPUT)/test_memcontrol: cgroup_util.c
+$(OUTPUT)/test_pids: cgroup_util.c
diff --git a/tools/testing/selftests/cgroup/test_pids.c b/tools/testing/selftests/cgroup/test_pids.c
new file mode 100644
index 000000000000..6545d81f2838
--- /dev/null
+++ b/tools/testing/selftests/cgroup/test_pids.c
@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+
+#include <errno.h>
+#include <linux/limits.h>
+#include <signal.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "../kselftest.h"
+#include "cgroup_util.h"
+
+static int run_success(const char *cgroup, void *arg)
+{
+ return 0;
+}
+
+static int run_pause(const char *cgroup, void *arg)
+{
+ return pause();
+}
+
+/*
+ * This test checks that pids.max prevents forking new children above the
+ * specified limit in the cgroup.
+ */
+static int test_pids_max(const char *root)
+{
+ int ret = KSFT_FAIL;
+ char *cg_pids;
+ int pid;
+
+
+ cg_pids = cg_name(root, "pids_test");
+ if (!cg_pids)
+ goto cleanup;
+
+ if (cg_create(cg_pids))
+ goto cleanup;
+
+ if (cg_read_strcmp(cg_pids, "pids.max", "max\n"))
+ goto cleanup;
+
+ if (cg_write(cg_pids, "pids.max", "2"))
+ goto cleanup;
+
+ if (cg_enter_current(cg_pids))
+ goto cleanup;
+
+ pid = cg_run_nowait(cg_pids, run_pause, NULL);
+ if (pid < 0)
+ goto cleanup;
+
+ if (cg_run_nowait(cg_pids, run_success, NULL) != -1 || errno != EAGAIN)
+ goto cleanup;
+
+ if (kill(pid, SIGINT))
+ goto cleanup;
+
+ ret = KSFT_PASS;
+
+cleanup:
+ cg_enter_current(root);
+ cg_destroy(cg_pids);
+ free(cg_pids);
+
+ return ret;
+}
+
+/*
+ * This test checks that while pids.max prevents forking new children above the
+ * specified limit in the cgroup appropriate events are generated in the
+ * hiearchy.
+ */
+static int test_pids_events(const char *root)
+{
+ int ret = KSFT_FAIL;
+ char *cg_parent = NULL, *cg_child = NULL;
+ int pid;
+
+
+ cg_parent = cg_name(root, "pids_parent");
+ cg_child = cg_name(cg_parent, "pids_child");
+ if (!cg_parent || !cg_child)
+ goto cleanup;
+
+ if (cg_create(cg_parent))
+ goto cleanup;
+ if (cg_write(cg_parent, "cgroup.subtree_control", "+pids"))
+ goto cleanup;
+ if (cg_create(cg_child))
+ goto cleanup;
+
+ if (cg_write(cg_parent, "pids.max", "2"))
+ goto cleanup;
+
+ if (cg_read_strcmp(cg_child, "pids.max", "max\n"))
+ goto cleanup;
+
+ if (cg_enter_current(cg_child))
+ goto cleanup;
+
+ pid = cg_run_nowait(cg_child, run_pause, NULL);
+ if (pid < 0)
+ goto cleanup;
+
+ if (cg_run_nowait(cg_child, run_success, NULL) != -1 || errno != EAGAIN)
+ goto cleanup;
+
+ if (kill(pid, SIGINT))
+ goto cleanup;
+
+
+ if (cg_read_key_long(cg_child, "pids.events", "max ") != 0)
+ goto cleanup;
+ if (cg_read_key_long(cg_child, "pids.events", "max.imposed ") != 1)
+ goto cleanup;
+
+ if (cg_read_key_long(cg_parent, "pids.events", "max ") != 1)
+ goto cleanup;
+ if (cg_read_key_long(cg_parent, "pids.events", "max.imposed ") != 1)
+ goto cleanup;
+
+
+ ret = KSFT_PASS;
+
+cleanup:
+ cg_enter_current(root);
+ if (cg_child)
+ cg_destroy(cg_child);
+ if (cg_parent)
+ cg_destroy(cg_parent);
+ free(cg_child);
+ free(cg_parent);
+
+ return ret;
+}
+
+
+
+#define T(x) { x, #x }
+struct pids_test {
+ int (*fn)(const char *root);
+ const char *name;
+} tests[] = {
+ T(test_pids_max),
+ T(test_pids_events),
+};
+#undef T
+
+int main(int argc, char **argv)
+{
+ char root[PATH_MAX];
+ int i, ret = EXIT_SUCCESS;
+
+ if (cg_find_unified_root(root, sizeof(root)))
+ ksft_exit_skip("cgroup v2 isn't mounted\n");
+
+ /*
+ * Check that pids controller is available:
+ * pids is listed in cgroup.controllers
+ */
+ if (cg_read_strstr(root, "cgroup.controllers", "pids"))
+ ksft_exit_skip("pids controller isn't available\n");
+
+ if (cg_read_strstr(root, "cgroup.subtree_control", "pids"))
+ if (cg_write(root, "cgroup.subtree_control", "+pids"))
+ ksft_exit_skip("Failed to set pids controller\n");
+
+ for (i = 0; i < ARRAY_SIZE(tests); i++) {
+ switch (tests[i].fn(root)) {
+ case KSFT_PASS:
+ ksft_test_result_pass("%s\n", tests[i].name);
+ break;
+ case KSFT_SKIP:
+ ksft_test_result_skip("%s\n", tests[i].name);
+ break;
+ default:
+ ret = EXIT_FAILURE;
+ ksft_test_result_fail("%s\n", tests[i].name);
+ break;
+ }
+ }
+
+ return ret;
+}
--
2.24.1
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