Commit 9bd5910d authored by Christian Brauner's avatar Christian Brauner Committed by Tejun Heo
Browse files

selftests/cgroup: add tests for cloning into cgroups 



Expand the cgroup test-suite to include tests for CLONE_INTO_CGROUP.
This adds the following tests:
- CLONE_INTO_CGROUP manages to clone a process directly into a correctly
  delegated cgroup
- CLONE_INTO_CGROUP fails to clone a process into a cgroup that has been
  removed after we've opened an fd to it
- CLONE_INTO_CGROUP fails to clone a process into an invalid domain
  cgroup
- CLONE_INTO_CGROUP adheres to the no internal process constraint
- CLONE_INTO_CGROUP works with the freezer feature

Cc: Tejun Heo <tj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: cgroups@vger.kernel.org
Cc: linux-kselftest@vger.kernel.org
Acked-by: default avatarRoman Gushchin <guro@fb.com>
Signed-off-by: default avatarChristian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent ef2c41cf

tools/testing/selftests/cgroup/Makefile

+3 −3
Original line number Diff line number Diff line
@@ -11,6 +11,6 @@ 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
 
$(OUTPUT)/test_memcontrol: cgroup_util.c ../clone3/clone3_selftests.h

$(OUTPUT)/test_core: cgroup_util.c ../clone3/clone3_selftests.h

$(OUTPUT)/test_freezer: cgroup_util.c ../clone3/clone3_selftests.h

tools/testing/selftests/cgroup/cgroup_util.c

+126 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
#include <unistd.h>



#include "cgroup_util.h"

#include "../clone3/clone3_selftests.h"



static ssize_t read_text(const char *path, char *buf, size_t max_len)

{
@@ -331,12 +332,112 @@ int cg_run(const char *cgroup, 
	}

}



pid_t clone_into_cgroup(int cgroup_fd)

{

#ifdef CLONE_ARGS_SIZE_VER2

	pid_t pid;



	struct clone_args args = {

		.flags = CLONE_INTO_CGROUP,

		.exit_signal = SIGCHLD,

		.cgroup = cgroup_fd,

	};



	pid = sys_clone3(&args, sizeof(struct clone_args));

	/*

	 * Verify that this is a genuine test failure:

	 * ENOSYS -> clone3() not available

	 * E2BIG  -> CLONE_INTO_CGROUP not available

	 */

	if (pid < 0 && (errno == ENOSYS || errno == E2BIG))

		goto pretend_enosys;



	return pid;



pretend_enosys:

#endif

	errno = ENOSYS;

	return -ENOSYS;

}



int clone_reap(pid_t pid, int options)

{

	int ret;

	siginfo_t info = {

		.si_signo = 0,

	};



again:

	ret = waitid(P_PID, pid, &info, options | __WALL | __WNOTHREAD);

	if (ret < 0) {

		if (errno == EINTR)

			goto again;

		return -1;

	}



	if (options & WEXITED) {

		if (WIFEXITED(info.si_status))

			return WEXITSTATUS(info.si_status);

	}



	if (options & WSTOPPED) {

		if (WIFSTOPPED(info.si_status))

			return WSTOPSIG(info.si_status);

	}



	if (options & WCONTINUED) {

		if (WIFCONTINUED(info.si_status))

			return 0;

	}



	return -1;

}



int dirfd_open_opath(const char *dir)

{

	return open(dir, O_DIRECTORY | O_CLOEXEC | O_NOFOLLOW | O_PATH);

}



#define close_prot_errno(fd)                                                   \

	if (fd >= 0) {                                                         \

		int _e_ = errno;                                               \

		close(fd);                                                     \

		errno = _e_;                                                   \

	}



static int clone_into_cgroup_run_nowait(const char *cgroup,

					int (*fn)(const char *cgroup, void *arg),

					void *arg)

{

	int cgroup_fd;

	pid_t pid;



	cgroup_fd =  dirfd_open_opath(cgroup);

	if (cgroup_fd < 0)

		return -1;



	pid = clone_into_cgroup(cgroup_fd);

	close_prot_errno(cgroup_fd);

	if (pid == 0)

		exit(fn(cgroup, arg));



	return pid;

}



int cg_run_nowait(const char *cgroup,

		  int (*fn)(const char *cgroup, void *arg),

		  void *arg)

{

	int pid;



	pid = clone_into_cgroup_run_nowait(cgroup, fn, arg);

	if (pid > 0)

		return pid;



	/* Genuine test failure. */

	if (pid < 0 && errno != ENOSYS)

		return -1;



	pid = fork();

	if (pid == 0) {

		char buf[64];
@@ -450,3 +551,28 @@ int proc_read_strstr(int pid, bool thread, const char *item, const char *needle) 


	return strstr(buf, needle) ? 0 : -1;

}



int clone_into_cgroup_run_wait(const char *cgroup)

{

	int cgroup_fd;

	pid_t pid;



	cgroup_fd =  dirfd_open_opath(cgroup);

	if (cgroup_fd < 0)

		return -1;



	pid = clone_into_cgroup(cgroup_fd);

	close_prot_errno(cgroup_fd);

	if (pid < 0)

		return -1;



	if (pid == 0)

		exit(EXIT_SUCCESS);



	/*

	 * We don't care whether this fails. We only care whether the initial

	 * clone succeeded.

	 */

	(void)clone_reap(pid, WEXITED);

	return 0;

}

tools/testing/selftests/cgroup/cgroup_util.h

+4 −0
Original line number Diff line number Diff line
@@ -50,3 +50,7 @@ extern int cg_wait_for_proc_count(const char *cgroup, int count); 
extern int cg_killall(const char *cgroup);

extern ssize_t proc_read_text(int pid, bool thread, const char *item, char *buf, size_t size);

extern int proc_read_strstr(int pid, bool thread, const char *item, const char *needle);

extern pid_t clone_into_cgroup(int cgroup_fd);

extern int clone_reap(pid_t pid, int options);

extern int clone_into_cgroup_run_wait(const char *cgroup);

extern int dirfd_open_opath(const char *dir);

tools/testing/selftests/cgroup/test_core.c

+64 −0
Original line number Diff line number Diff line
@@ -137,8 +137,11 @@ cleanup: 
static int test_cgcore_populated(const char *root)

{

	int ret = KSFT_FAIL;

	int err;

	char *cg_test_a = NULL, *cg_test_b = NULL;

	char *cg_test_c = NULL, *cg_test_d = NULL;

	int cgroup_fd = -EBADF;

	pid_t pid;



	cg_test_a = cg_name(root, "cg_test_a");

	cg_test_b = cg_name(root, "cg_test_a/cg_test_b");
@@ -190,6 +193,52 @@ static int test_cgcore_populated(const char *root) 
	if (cg_read_strcmp(cg_test_d, "cgroup.events", "populated 0\n"))

		goto cleanup;



	/* Test that we can directly clone into a new cgroup. */

	cgroup_fd = dirfd_open_opath(cg_test_d);

	if (cgroup_fd < 0)

		goto cleanup;



	pid = clone_into_cgroup(cgroup_fd);

	if (pid < 0) {

		if (errno == ENOSYS)

			goto cleanup_pass;

		goto cleanup;

	}



	if (pid == 0) {

		if (raise(SIGSTOP))

			exit(EXIT_FAILURE);

		exit(EXIT_SUCCESS);

	}



	err = cg_read_strcmp(cg_test_d, "cgroup.events", "populated 1\n");



	(void)clone_reap(pid, WSTOPPED);

	(void)kill(pid, SIGCONT);

	(void)clone_reap(pid, WEXITED);



	if (err)

		goto cleanup;



	if (cg_read_strcmp(cg_test_d, "cgroup.events", "populated 0\n"))

		goto cleanup;



	/* Remove cgroup. */

	if (cg_test_d) {

		cg_destroy(cg_test_d);

		free(cg_test_d);

		cg_test_d = NULL;

	}



	pid = clone_into_cgroup(cgroup_fd);

	if (pid < 0)

		goto cleanup_pass;

	if (pid == 0)

		exit(EXIT_SUCCESS);

	(void)clone_reap(pid, WEXITED);

	goto cleanup;



cleanup_pass:

	ret = KSFT_PASS;



cleanup:
@@ -205,6 +254,8 @@ cleanup: 
	free(cg_test_c);

	free(cg_test_b);

	free(cg_test_a);

	if (cgroup_fd >= 0)

		close(cgroup_fd);

	return ret;

}
@@ -248,6 +299,16 @@ static int test_cgcore_invalid_domain(const char *root) 
	if (errno != EOPNOTSUPP)

		goto cleanup;



	if (!clone_into_cgroup_run_wait(child))

		goto cleanup;



	if (errno == ENOSYS)

		goto cleanup_pass;



	if (errno != EOPNOTSUPP)

		goto cleanup;



cleanup_pass:

	ret = KSFT_PASS;



cleanup:
@@ -457,6 +518,9 @@ static int test_cgcore_internal_process_constraint(const char *root) 
	if (!cg_enter_current(parent))

		goto cleanup;



	if (!clone_into_cgroup_run_wait(parent))

		goto cleanup;



	ret = KSFT_PASS;



cleanup:

tools/testing/selftests/clone3/clone3_selftests.h

+17 −2
Original line number Diff line number Diff line
@@ -5,12 +5,24 @@ 


#define _GNU_SOURCE

#include <sched.h>

#include <linux/sched.h>

#include <linux/types.h>

#include <stdint.h>

#include <syscall.h>

#include <linux/types.h>

#include <sys/wait.h>



#include "../kselftest.h"



#define ptr_to_u64(ptr) ((__u64)((uintptr_t)(ptr)))



#ifndef CLONE_INTO_CGROUP

#define CLONE_INTO_CGROUP 0x200000000ULL /* Clone into a specific cgroup given the right permissions. */

#endif



#ifndef CLONE_ARGS_SIZE_VER0

#define CLONE_ARGS_SIZE_VER0 64

#endif



#ifndef __NR_clone3

#define __NR_clone3 -1

struct clone_args {
@@ -22,10 +34,13 @@ struct clone_args { 
	__aligned_u64 stack;

	__aligned_u64 stack_size;

	__aligned_u64 tls;

#define CLONE_ARGS_SIZE_VER1 80

	__aligned_u64 set_tid;

	__aligned_u64 set_tid_size;

#define CLONE_ARGS_SIZE_VER2 88

	__aligned_u64 cgroup;

};

#endif

#endif /* __NR_clone3 */



static pid_t sys_clone3(struct clone_args *args, size_t size)

{

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