Re: [PATCH v4 6/6] selftests/cgroup: add tests for cloning into cgroups

On Fri, Jan 17, 2020 at 07:12:19PM +0100, Christian Brauner wrote:

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: Roman Gushchin guro@fb.com Cc: Tejun Heo tj@kernel.org Cc: Shuah Khan shuah@kernel.org Cc: cgroups@vger.kernel.org Cc: linux-kselftest@vger.kernel.org Signed-off-by: Christian Brauner christian.brauner@ubuntu.com

Acked-by: Roman Gushchin guro@fb.com

Thank you for adding tests!

---

/* v1 */ Link: https://lore.kernel.org/r/20191218173516.7875-4-christian.brauner@ubuntu.com

/* v2 */ Link: https://lore.kernel.org/r/20191223061504.28716-4-christian.brauner@ubuntu.co... unchanged

/* v3 */ Link: https://lore.kernel.org/r/20200117002143.15559-6-christian.brauner@ubuntu.co... unchanged

/* v3 */

v4?

unchanged

tools/testing/selftests/cgroup/Makefile | 6 +- tools/testing/selftests/cgroup/cgroup_util.c | 126 ++++++++++++++++++ tools/testing/selftests/cgroup/cgroup_util.h | 4 + tools/testing/selftests/cgroup/test_core.c | 64 +++++++++ .../selftests/clone3/clone3_selftests.h | 19 ++- 5 files changed, 214 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/cgroup/Makefile b/tools/testing/selftests/cgroup/Makefile index 66aafe1f5746..967f268fde74 100644 --- a/tools/testing/selftests/cgroup/Makefile +++ b/tools/testing/selftests/cgroup/Makefile @@ -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 diff --git a/tools/testing/selftests/cgroup/cgroup_util.c b/tools/testing/selftests/cgroup/cgroup_util.c index 8f7131dcf1ff..8a637ca7d73a 100644 --- a/tools/testing/selftests/cgroup/cgroup_util.c +++ b/tools/testing/selftests/cgroup/cgroup_util.c @@ -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;

+} diff --git a/tools/testing/selftests/cgroup/cgroup_util.h b/tools/testing/selftests/cgroup/cgroup_util.h index 49c54fbdb229..5a1305dd1f0b 100644 --- a/tools/testing/selftests/cgroup/cgroup_util.h +++ b/tools/testing/selftests/cgroup/cgroup_util.h @@ -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); diff --git a/tools/testing/selftests/cgroup/test_core.c b/tools/testing/selftests/cgroup/test_core.c index c5ca669feb2b..96e016ccafe0 100644 --- a/tools/testing/selftests/cgroup/test_core.c +++ b/tools/testing/selftests/cgroup/test_core.c @@ -25,8 +25,11 @@ 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"); @@ -78,6 +81,52 @@ 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: @@ -93,6 +142,8 @@ static int test_cgcore_populated(const char *root) free(cg_test_c); free(cg_test_b); free(cg_test_a);

• if (cgroup_fd >= 0)

• close(cgroup_fd);
  

  return ret;

} @@ -136,6 +187,16 @@ 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: @@ -345,6 +406,9 @@ 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: diff --git a/tools/testing/selftests/clone3/clone3_selftests.h b/tools/testing/selftests/clone3/clone3_selftests.h index a3f2c8ad8bcc..91c1a78ddb39 100644 --- a/tools/testing/selftests/clone3/clone3_selftests.h +++ b/tools/testing/selftests/clone3/clone3_selftests.h @@ -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) { -- 2.25.0