This patch implements 8 tests for the freezer controller for
cgroup v2:
1) a simple test, which aims to freeze and unfreeze a cgroup with 100
processes
2) a more complicated tree test, which creates a hierarchy of cgroups,
puts some processes in some cgroups, and tries to freeze and unfreeze
different parts of the subtree
3) a forkbomb test: the test aims to freeze a forkbomb running in a
cgroup, kill all tasks in the cgroup and remove the cgroup without
the unfreezing.
4) rmdir test: the test creates two nested cgroups, freezes the parent
one, checks that the child can be successfully removed, and a new
child can be created
5) migration tests: the test checks migration of a task between
frozen cgroups: from a frozen to a running, from a running to a
frozen, and from a frozen to a frozen.
6) ptrace test: the test checks that it's possible to attach to
a process in a frozen cgroup, get some information and detach, and
the cgroup will remain frozen.
7) stopped test: the test checks that it's possible to freeze a cgroup
with a stopped task
8) ptraced test: the test checks that it's possible to freeze a cgroup
with a ptraced task
Expected output:
$ ./test_freezer
ok 1 test_cgfreezer_simple
ok 2 test_cgfreezer_tree
ok 3 test_cgfreezer_forkbomb
ok 4 test_cgrreezer_rmdir
ok 5 test_cgfreezer_migrate
ok 6 test_cgfreezer_ptrace
ok 7 test_cgfreezer_stopped
ok 8 test_cgfreezer_ptraced
Signed-off-by: Roman Gushchin <guro@xxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: kernel-team@xxxxxx
Cc: linux-kselftest@xxxxxxxxxxxxxxx
---
tools/testing/selftests/cgroup/.gitignore | 1 +
tools/testing/selftests/cgroup/Makefile | 2 +
tools/testing/selftests/cgroup/cgroup_util.c | 81 +-
tools/testing/selftests/cgroup/cgroup_util.h | 7 +
tools/testing/selftests/cgroup/test_freezer.c | 842 ++++++++++++++++++
5 files changed, 932 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/cgroup/test_freezer.c
diff --git a/tools/testing/selftests/cgroup/.gitignore b/tools/testing/selftests/cgroup/.gitignore
index adacda50a4b2..7f9835624793 100644
--- a/tools/testing/selftests/cgroup/.gitignore
+++ b/tools/testing/selftests/cgroup/.gitignore
@@ -1,2 +1,3 @@
test_memcontrol
test_core
+test_freezer
diff --git a/tools/testing/selftests/cgroup/Makefile b/tools/testing/selftests/cgroup/Makefile
index 23fbaa4a9630..8d369b6a2069 100644
--- a/tools/testing/selftests/cgroup/Makefile
+++ b/tools/testing/selftests/cgroup/Makefile
@@ -5,8 +5,10 @@ all:
TEST_GEN_PROGS = test_memcontrol
TEST_GEN_PROGS += test_core
+TEST_GEN_PROGS += test_freezer
include ../lib.mk
$(OUTPUT)/test_memcontrol: cgroup_util.c
$(OUTPUT)/test_core: cgroup_util.c
+$(OUTPUT)/test_freezer: cgroup_util.c
diff --git a/tools/testing/selftests/cgroup/cgroup_util.c b/tools/testing/selftests/cgroup/cgroup_util.c
index eba06f94433b..e9cdad673901 100644
--- a/tools/testing/selftests/cgroup/cgroup_util.c
+++ b/tools/testing/selftests/cgroup/cgroup_util.c
@@ -74,6 +74,16 @@ char *cg_name_indexed(const char *root, const char *name, int index)
return ret;
}
+char *cg_control(const char *cgroup, const char *control)
+{
+ size_t len = strlen(cgroup) + strlen(control) + 2;
+ char *ret = malloc(len);
+
+ snprintf(ret, len, "%s/%s", cgroup, control);
+
+ return ret;
+}
+
int cg_read(const char *cgroup, const char *control, char *buf, size_t len)
{
char path[PATH_MAX];
@@ -196,7 +206,59 @@ int cg_create(const char *cgroup)
return mkdir(cgroup, 0644);
}
-static int cg_killall(const char *cgroup)
+int cg_for_all_procs(const char *cgroup, int (*fn)(int pid, void *arg),
+ void *arg)
+{
+ char buf[PAGE_SIZE];
+ char *ptr = buf;
+ int ret;
+
+ if (cg_read(cgroup, "cgroup.procs", buf, sizeof(buf)))
+ return -1;
+
+ while (ptr < buf + sizeof(buf)) {
+ int pid = strtol(ptr, &ptr, 10);
+
+ if (pid == 0)
+ break;
+ if (*ptr)
+ ptr++;
+ else
+ break;
+ ret = fn(pid, arg);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+int cg_wait_for_proc_count(const char *cgroup, int count)
+{
+ char buf[10 * PAGE_SIZE] = {0};
+ int attempts;
+ char *ptr;
+
+ for (attempts = 10; attempts >= 0; attempts--) {
+ int nr = 0;
+
+ if (cg_read(cgroup, "cgroup.procs", buf, sizeof(buf)))
+ break;
+
+ for (ptr = buf; *ptr; ptr++)
+ if (*ptr == '\n')
+ nr++;
+
+ if (nr >= count)
+ return 0;
+
+ usleep(100000);
+ }
+
+ return -1;
+}
+
+int cg_killall(const char *cgroup)
{
char buf[PAGE_SIZE];
char *ptr = buf;
@@ -238,6 +300,14 @@ int cg_destroy(const char *cgroup)
return ret;
}
+int cg_enter(const char *cgroup, int pid)
+{
+ char pidbuf[64];
+
+ snprintf(pidbuf, sizeof(pidbuf), "%d", pid);
+ return cg_write(cgroup, "cgroup.procs", pidbuf);
+}
+
int cg_enter_current(const char *cgroup)
{
char pidbuf[64];
@@ -367,3 +437,12 @@ int set_oom_adj_score(int pid, int score)
close(fd);
return 0;
}
+
+char proc_read_text(int pid, const char *item, char *buf, size_t size)
+{
+ char path[PATH_MAX];
+
+ snprintf(path, sizeof(path), "/proc/%d/%s", pid, item);
+
+ return read_text(path, buf, size);
+}
diff --git a/tools/testing/selftests/cgroup/cgroup_util.h b/tools/testing/selftests/cgroup/cgroup_util.h
index 9ac8b7958f83..8ee63c00a668 100644
--- a/tools/testing/selftests/cgroup/cgroup_util.h
+++ b/tools/testing/selftests/cgroup/cgroup_util.h
@@ -18,6 +18,7 @@ static inline int values_close(long a, long b, int err)
extern int cg_find_unified_root(char *root, size_t len);
extern char *cg_name(const char *root, const char *name);
extern char *cg_name_indexed(const char *root, const char *name, int index);
+extern char *cg_control(const char *cgroup, const char *control);
extern int cg_create(const char *cgroup);
extern int cg_destroy(const char *cgroup);
extern int cg_read(const char *cgroup, const char *control,
@@ -32,6 +33,7 @@ extern int cg_write(const char *cgroup, const char *control, char *buf);
extern int cg_run(const char *cgroup,
int (*fn)(const char *cgroup, void *arg),
void *arg);
+extern int cg_enter(const char *cgroup, int pid);
extern int cg_enter_current(const char *cgroup);
extern int cg_run_nowait(const char *cgroup,
int (*fn)(const char *cgroup, void *arg),
@@ -41,3 +43,8 @@ extern int alloc_pagecache(int fd, size_t size);
extern int alloc_anon(const char *cgroup, void *arg);
extern int is_swap_enabled(void);
extern int set_oom_adj_score(int pid, int score);
+extern int cg_for_all_procs(const char *cgroup, int (*fn)(int pid, void *arg),
+ void *arg);
+extern int cg_wait_for_proc_count(const char *cgroup, int count);
+extern int cg_killall(const char *cgroup);
+extern char proc_read_text(int pid, const char *item, char *buf, size_t size);
diff --git a/tools/testing/selftests/cgroup/test_freezer.c b/tools/testing/selftests/cgroup/test_freezer.c
new file mode 100644
index 000000000000..c11176a92474
--- /dev/null
+++ b/tools/testing/selftests/cgroup/test_freezer.c
@@ -0,0 +1,842 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <stdbool.h>
+#include <linux/limits.h>
+#include <sys/ptrace.h>
+#include <sys/types.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <errno.h>
+#include <poll.h>
+#include <stdlib.h>
+#include <sys/inotify.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include "../kselftest.h"
+#include "cgroup_util.h"
+
+#define DEBUG
+#ifdef DEBUG
+#define debug(args...) fprintf(stderr, args)
+#else
+#define debug(args...)
+#endif
+
+/*
+ * Freeze the given cgroup and wait for the inotify signal.
+ * If there is no signal in 10 seconds, treat this as an error.
+ */
+static int cg_freeze_wait(const char *cgroup, bool freeze)
+{
+ int fd, wd;
+ struct pollfd fds;
+ int ret = -1;
+
+ fd = inotify_init1(IN_NONBLOCK);
+ if (fd == -1)
+ return fd;
+
+ wd = inotify_add_watch(fd, cg_control(cgroup, "cgroup.events"),
+ IN_MODIFY);
+ if (wd == -1) {
+ close(fd);
+ return wd;
+ }
+ fds.fd = fd;
+ fds.events = POLLIN;
+
+ ret = cg_write(cgroup, "cgroup.freeze", freeze ? "1" : "0");
+ if (ret) {
+ close(fd);
+ return ret;
+ }
+
+ while (true) {
+ wd = poll(&fds, 1, 10000);
+
+ if (wd == -1 && errno == EINTR)
+ continue;
+
+ if (wd == 1 && fds.revents & POLLIN)
+ ret = 0;
+
+ break;
+ }
+
+ close(fd);
+
+ return ret;
+}
+
+/*
+ * Check if the process is frozen and parked in a proper place.
+ */
+static int proc_check_frozen(int pid, void *arg)
+{
+ char buf[PAGE_SIZE];
+ int len;
+
+ len = proc_read_text(pid, "stat", buf, sizeof(buf));
+ if (len == -1) {
+ debug("Can't get %d stat\n", pid);
+ return -1;
+ }
+
+ if (strstr(buf, "(test_freezer) S ") == NULL) {
+ debug("Process %d in the unexpected state: %s\n", pid, buf);
+ return -1;
+ }
+
+ len = proc_read_text(pid, "stack", buf, sizeof(buf));
+ if (len == -1) {
+ debug("Can't get stack of the process %d\n", pid);
+ return -1;
+ }
+
+ if (strstr(buf, "[<0>] get_signal") != buf) {
+ debug("Process %d has unexpected stacktrace: %s\n", pid, buf);
+ return -1;
+ }
+
+ return 0;
+}
+
+/*
+ * Check if the cgroup is frozen by looking at the cgroup.events::frozen value.
+ */
+static int __cg_check_frozen(const char *cgroup, bool frozen)
+{
+ if (frozen) {
+ if (cg_read_strstr(cgroup, "cgroup.events", "frozen 1") != 0) {
+ debug("Cgroup %s isn't unexpectedly frozen\n", cgroup);
+ return -1;
+ }
+ } else {
+ /*
+ * Check the cgroup.events::frozen value.
+ */
+ if (cg_read_strstr(cgroup, "cgroup.events", "frozen 0") != 0) {
+ debug("Cgroup %s is unexpectedly frozen\n", cgroup);
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * Check if the cgroup is frozen and all belonging processes are
+ * parked in a proper place.
+ */
+static int cg_check_frozen(const char *cgroup, bool frozen)
+{
+ if (__cg_check_frozen(cgroup, frozen))
+ return -1;
+
+ /*
+ * Check that all processes are parked in the proper place.
+ */
+ if (frozen && cg_for_all_procs(cgroup, proc_check_frozen, NULL)) {
+ debug("Some processes of cgroup %s are not frozen\n",
+ cgroup);
+ return -1;
+ }
+
+ return 0;
+}
+
+/*
+ * A simple process running in a sleep loop until being
+ * re-parented.
+ */
+static int child_fn(const char *cgroup, void *arg)
+{
+ int ppid = getppid();
+
+ while (getppid() == ppid)
+ usleep(1000);
+
+ return getppid() == ppid;
+}
+
+/*
+ * A simple test for the cgroup freezer: populated the cgroup with 100
+ * running processes and freeze it. Then unfreeze it. Then it kills all
+ * processes and destroys the cgroup.
+ */
+static int test_cgfreezer_simple(const char *root)
+{
+ int ret = KSFT_FAIL;
+ char *cgroup = NULL;
+ int i;
+
+ cgroup = cg_name(root, "cg_test");
+ if (!cgroup)
+ goto cleanup;
+
+ if (cg_create(cgroup))
+ goto cleanup;
+
+ for (i = 0; i < 100; i++)
+ cg_run_nowait(cgroup, child_fn, NULL);
+
+ if (cg_wait_for_proc_count(cgroup, 100))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup, false))
+ goto cleanup;
+
+ if (cg_freeze_wait(cgroup, true))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup, true))
+ goto cleanup;
+
+ if (cg_freeze_wait(cgroup, false))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup, false))
+ goto cleanup;
+
+ ret = KSFT_PASS;
+
+cleanup:
+ if (cgroup)
+ cg_destroy(cgroup);
+ free(cgroup);
+ return ret;
+}
+
+/*
+ * The test creates the following hierarchy:
+ * A
+ * / / \ \
+ * B E I K
+ * /\ |
+ * C D F
+ * |
+ * G
+ * |
+ * H
+ *
+ * with a process in C, H and 3 processes in K.
+ * Then it tries to freeze and unfreeze the whole tree.
+ */
+static int test_cgfreezer_tree(const char *root)
+{
+ char *cgroup[10] = {0};
+ int ret = KSFT_FAIL;
+ int i;
+
+ cgroup[0] = cg_name(root, "cg_test_A");
+ if (!cgroup[0])
+ goto cleanup;
+
+ cgroup[1] = cg_name(cgroup[0], "cg_test_B");
+ if (!cgroup[1])
+ goto cleanup;
+
+ cgroup[2] = cg_name(cgroup[1], "cg_test_C");
+ if (!cgroup[2])
+ goto cleanup;
+
+ cgroup[3] = cg_name(cgroup[1], "cg_test_D");
+ if (!cgroup[3])
+ goto cleanup;
+
+ cgroup[4] = cg_name(cgroup[0], "cg_test_E");
+ if (!cgroup[4])
+ goto cleanup;
+
+ cgroup[5] = cg_name(cgroup[4], "cg_test_F");
+ if (!cgroup[5])
+ goto cleanup;
+
+ cgroup[6] = cg_name(cgroup[5], "cg_test_G");
+ if (!cgroup[6])
+ goto cleanup;
+
+ cgroup[7] = cg_name(cgroup[6], "cg_test_H");
+ if (!cgroup[7])
+ goto cleanup;
+
+ cgroup[8] = cg_name(cgroup[0], "cg_test_I");
+ if (!cgroup[8])
+ goto cleanup;
+
+ cgroup[9] = cg_name(cgroup[0], "cg_test_K");
+ if (!cgroup[9])
+ goto cleanup;
+
+ for (i = 0; i < 10; i++)
+ if (cg_create(cgroup[i]))
+ goto cleanup;
+
+ cg_run_nowait(cgroup[2], child_fn, NULL);
+ cg_run_nowait(cgroup[7], child_fn, NULL);
+ cg_run_nowait(cgroup[9], child_fn, NULL);
+ cg_run_nowait(cgroup[9], child_fn, NULL);
+ cg_run_nowait(cgroup[9], child_fn, NULL);
+
+ /*
+ * Wait until all child processes will enter
+ * corresponding cgroups.
+ */
+
+ if (cg_wait_for_proc_count(cgroup[2], 1) ||
+ cg_wait_for_proc_count(cgroup[7], 1) ||
+ cg_wait_for_proc_count(cgroup[9], 3))
+ goto cleanup;
+
+ /*
+ * Freeze B.
+ */
+ if (cg_freeze_wait(cgroup[1], true))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup[1], true))
+ goto cleanup;
+
+ /*
+ * Freeze F.
+ */
+ if (cg_freeze_wait(cgroup[5], true))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup[5], true))
+ goto cleanup;
+
+ /*
+ * Freeze G.
+ */
+ if (cg_freeze_wait(cgroup[6], true))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup[6], true))
+ goto cleanup;
+
+ /*
+ * Check that A and E are not frozen.
+ */
+ if (cg_check_frozen(cgroup[0], false))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup[4], false))
+ goto cleanup;
+
+ /*
+ * Freeze A. Check that A, B and E are frozen.
+ */
+ if (cg_freeze_wait(cgroup[0], true))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup[0], true))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup[1], true))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup[4], true))
+ goto cleanup;
+
+ /*
+ * Unfreeze B, F and G
+ */
+ if (cg_freeze_wait(cgroup[1], false))
+ goto cleanup;
+
+ if (cg_freeze_wait(cgroup[5], false))
+ goto cleanup;
+
+ if (cg_freeze_wait(cgroup[6], false))
+ goto cleanup;
+
+ /*
+ * Check that C and H are still frozen.
+ */
+ if (cg_check_frozen(cgroup[2], true))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup[7], true))
+ goto cleanup;
+
+ /*
+ * Unfreezing A failed. Check that A, C and K are not frozen.
+ */
+ if (cg_freeze_wait(cgroup[0], false))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup[0], false))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup[2], false))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup[9], false))
+ goto cleanup;
+
+ ret = KSFT_PASS;
+
+cleanup:
+ for (i = 9; i >= 0 && cgroup[i]; i--) {
+ cg_destroy(cgroup[i]);
+ free(cgroup[i]);
+ }
+
+ return ret;
+}
+
+/*
+ * A fork bomb emulator.
+ */
+static int forkbomb_fn(const char *cgroup, void *arg)
+{
+ int ppid;
+
+ fork();
+ fork();
+
+ ppid = getppid();
+
+ while (getppid() == ppid)
+ usleep(1000);
+
+ return getppid() == ppid;
+}
+
+/*
+ * The test runs a fork bomb in a cgroup and tries to freeze it.
+ * Then it kills all processes and checks that cgroup isn't populated
+ * anymore.
+ */
+static int test_cgfreezer_forkbomb(const char *root)
+{
+ int ret = KSFT_FAIL;
+ char *cgroup = NULL;
+
+ cgroup = cg_name(root, "cg_forkbomb_test");
+ if (!cgroup)
+ goto cleanup;
+
+ if (cg_create(cgroup))
+ goto cleanup;
+
+ cg_run_nowait(cgroup, forkbomb_fn, NULL);
+
+ usleep(100000);
+
+ if (cg_freeze_wait(cgroup, true))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup, true))
+ goto cleanup;
+
+ if (cg_killall(cgroup))
+ goto cleanup;
+
+ if (cg_wait_for_proc_count(cgroup, 0))
+ goto cleanup;
+
+ ret = KSFT_PASS;
+
+cleanup:
+ if (cgroup)
+ cg_destroy(cgroup);
+ free(cgroup);
+ return ret;
+}
+
+/*
+ * The test creates two nested cgroups, freezes the parent
+ * and removes the child. Then it checks that the parent cgroup
+ * remains frozen and it's possible to create a new child
+ * without unfreezing. The new child is frozen too.
+ */
+static int test_cgfreezer_rmdir(const char *root)
+{
+ int ret = KSFT_FAIL;
+ char *parent, *child = NULL;
+
+ parent = cg_name(root, "cg_test_A");
+ if (!parent)
+ goto cleanup;
+
+ child = cg_name(parent, "cg_test_B");
+ if (!child)
+ goto cleanup;
+
+ if (cg_create(parent))
+ goto cleanup;
+
+ if (cg_create(child))
+ goto cleanup;
+
+ if (cg_freeze_wait(parent, true))
+ goto cleanup;
+
+ if (cg_check_frozen(parent, true))
+ goto cleanup;
+
+ if (cg_destroy(child))
+ goto cleanup;
+
+ if (cg_check_frozen(parent, true))
+ goto cleanup;
+
+ if (cg_create(child))
+ goto cleanup;
+
+ if (cg_check_frozen(child, true))
+ goto cleanup;
+
+ ret = KSFT_PASS;
+
+cleanup:
+ if (child)
+ cg_destroy(child);
+ free(child);
+ if (parent)
+ cg_destroy(parent);
+ free(parent);
+ return ret;
+}
+
+/*
+ * The test creates two cgroups: A and B. The it runs a process in A,
+ * and performs several migrations:
+ * 1) A (running) -> B (frozen)
+ * 2) B (frozen) -> A (running)
+ * 3) A (frozen) -> B (frozen)
+ *
+ * One each step it checks that the actual state of cgroups matches
+ * the expected state.
+ */
+static int test_cgfreezer_migrate(const char *root)
+{
+ int ret = KSFT_FAIL;
+ char *cgroup[2] = {0};
+ int pid;
+
+ cgroup[0] = cg_name(root, "cg_test_A");
+ if (!cgroup[0])
+ goto cleanup;
+
+ cgroup[1] = cg_name(root, "cg_test_B");
+ if (!cgroup[1])
+ goto cleanup;
+
+ if (cg_create(cgroup[0]))
+ goto cleanup;
+
+ if (cg_create(cgroup[1]))
+ goto cleanup;
+
+ pid = cg_run_nowait(cgroup[0], child_fn, NULL);
+ if (pid < 0)
+ goto cleanup;
+
+ if (cg_wait_for_proc_count(cgroup[0], 1))
+ goto cleanup;
+
+ /*
+ * Migrate from A (running) to B (frozen)
+ */
+ if (cg_freeze_wait(cgroup[1], true))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup[1], true))
+ goto cleanup;
+
+ if (cg_enter(cgroup[1], pid))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup[0], false))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup[1], true))
+ goto cleanup;
+
+ /*
+ * Migrate from B (frozen) to A (running)
+ */
+ if (cg_enter(cgroup[0], pid))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup[0], false))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup[1], true))
+ goto cleanup;
+
+ /*
+ * Migrate from A (frozen) to B (frozen)
+ */
+ if (cg_freeze_wait(cgroup[0], true))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup[0], true))
+ goto cleanup;
+
+ if (cg_enter(cgroup[1], pid))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup[0], true))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup[1], true))
+ goto cleanup;
+
+ ret = KSFT_PASS;
+
+cleanup:
+ if (cgroup[0])
+ cg_destroy(cgroup[0]);
+ free(cgroup[0]);
+ if (cgroup[1])
+ cg_destroy(cgroup[1]);
+ free(cgroup[1]);
+ return ret;
+}
+
+/*
+ * The test checks that ptrace works with a tracing process in a frozen cgroup.
+ */
+static int test_cgfreezer_ptrace(const char *root)
+{
+ int ret = KSFT_FAIL;
+ char *cgroup = NULL;
+ siginfo_t siginfo;
+ int pid;
+
+ cgroup = cg_name(root, "cg_test");
+ if (!cgroup)
+ goto cleanup;
+
+ if (cg_create(cgroup))
+ goto cleanup;
+
+ pid = cg_run_nowait(cgroup, child_fn, NULL);
+ if (pid < 0)
+ goto cleanup;
+
+ if (cg_wait_for_proc_count(cgroup, 1))
+ goto cleanup;
+
+ if (cg_freeze_wait(cgroup, true))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup, true))
+ goto cleanup;
+
+ if (ptrace(PTRACE_SEIZE, pid, NULL, NULL))
+ goto cleanup;
+
+ if (ptrace(PTRACE_INTERRUPT, pid, NULL, NULL))
+ goto cleanup;
+
+ waitpid(pid, NULL, 0);
+
+ /*
+ * Cgroup has to remain frozen, however the test task
+ * is in traced state.
+ */
+ if (__cg_check_frozen(cgroup, true))
+ goto cleanup;
+
+ if (ptrace(PTRACE_GETSIGINFO, pid, NULL, &siginfo))
+ goto cleanup;
+
+ if (ptrace(PTRACE_DETACH, pid, NULL, NULL))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup, true))
+ goto cleanup;
+
+ ret = KSFT_PASS;
+
+cleanup:
+ if (cgroup)
+ cg_destroy(cgroup);
+ free(cgroup);
+ return ret;
+}
+
+/*
+ * Check if the process is stopped.
+ */
+static int proc_check_stopped(int pid)
+{
+ char buf[PAGE_SIZE];
+ int len;
+
+ len = proc_read_text(pid, "stat", buf, sizeof(buf));
+ if (len == -1) {
+ debug("Can't get %d stat\n", pid);
+ return -1;
+ }
+
+ if (strstr(buf, "(test_freezer) T ") == NULL) {
+ debug("Process %d in the unexpected state: %s\n", pid, buf);
+ return -1;
+ }
+
+ return 0;
+}
+
+/*
+ * Test that it's possible to freeze a cgroup with a stopped process.
+ */
+static int test_cgfreezer_stopped(const char *root)
+{
+ int pid, ret = KSFT_FAIL;
+ char *cgroup = NULL;
+
+ cgroup = cg_name(root, "cg_test");
+ if (!cgroup)
+ goto cleanup;
+
+ if (cg_create(cgroup))
+ goto cleanup;
+
+ pid = cg_run_nowait(cgroup, child_fn, NULL);
+
+ if (cg_wait_for_proc_count(cgroup, 1))
+ goto cleanup;
+
+ if (kill(pid, SIGSTOP))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup, false))
+ goto cleanup;
+
+ if (cg_freeze_wait(cgroup, true))
+ goto cleanup;
+
+ /*
+ * cg_check_frozen(cgroup, true) will fail here,
+ * because the task in in the STOPped state;
+ * but the cgroup is expected to be frozen.
+ */
+ if (__cg_check_frozen(cgroup, true))
+ goto cleanup;
+
+ if (cg_freeze_wait(cgroup, false))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup, false))
+ goto cleanup;
+
+ if (proc_check_stopped(pid))
+ goto cleanup;
+
+ ret = KSFT_PASS;
+
+cleanup:
+ if (cgroup)
+ cg_destroy(cgroup);
+ free(cgroup);
+ return ret;
+}
+
+/*
+ * Test that it's possible to freeze a cgroup with a ptraced process.
+ */
+static int test_cgfreezer_ptraced(const char *root)
+{
+ int pid, ret = KSFT_FAIL;
+ char *cgroup = NULL;
+ siginfo_t siginfo;
+
+ cgroup = cg_name(root, "cg_test");
+ if (!cgroup)
+ goto cleanup;
+
+ if (cg_create(cgroup))
+ goto cleanup;
+
+ pid = cg_run_nowait(cgroup, child_fn, NULL);
+
+ if (cg_wait_for_proc_count(cgroup, 1))
+ goto cleanup;
+
+ if (ptrace(PTRACE_SEIZE, pid, NULL, NULL))
+ goto cleanup;
+
+ if (ptrace(PTRACE_INTERRUPT, pid, NULL, NULL))
+ goto cleanup;
+
+ waitpid(pid, NULL, 0);
+
+ if (cg_check_frozen(cgroup, false))
+ goto cleanup;
+
+ if (cg_freeze_wait(cgroup, true))
+ goto cleanup;
+
+ /*
+ * cg_check_frozen(cgroup, true) will fail here,
+ * because the task in in the TRACEd state.
+ */
+ if (cg_freeze_wait(cgroup, false))
+ goto cleanup;
+
+ if (cg_check_frozen(cgroup, false))
+ goto cleanup;
+
+ if (ptrace(PTRACE_GETSIGINFO, pid, NULL, &siginfo))
+ goto cleanup;
+
+ if (ptrace(PTRACE_DETACH, pid, NULL, NULL))
+ goto cleanup;
+
+ ret = KSFT_PASS;
+
+cleanup:
+ if (cgroup)
+ cg_destroy(cgroup);
+ free(cgroup);
+ return ret;
+}
+
+#define T(x) { x, #x }
+struct cgfreezer_test {
+ int (*fn)(const char *root);
+ const char *name;
+} tests[] = {
+ T(test_cgfreezer_simple),
+ T(test_cgfreezer_tree),
+ T(test_cgfreezer_forkbomb),
+ T(test_cgfreezer_rmdir),
+ T(test_cgfreezer_migrate),
+ T(test_cgfreezer_ptrace),
+ T(test_cgfreezer_stopped),
+ T(test_cgfreezer_ptraced),
+};
+#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");
+ 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;
+}
--
2.20.1
