[LTP] [PATCH v2] kill01: New case cgroup kill

Li Wang liwang@redhat.com
Mon Mar 6 11:16:26 CET 2023


On Sun, Mar 5, 2023 at 5:14 PM Wei Gao via ltp <ltp@lists.linux.it> wrote:

> Signed-off-by: Wei Gao <wegao@suse.com>
> ---
>  lib/tst_cgroup.c                             |   1 +
>  runtest/controllers                          |   1 +
>  testcases/kernel/controllers/kill/.gitignore |   1 +
>  testcases/kernel/controllers/kill/Makefile   |   6 +
>  testcases/kernel/controllers/kill/kill01.c   | 130 +++++++++++++++++++
>  5 files changed, 139 insertions(+)
>  create mode 100644 testcases/kernel/controllers/kill/.gitignore
>  create mode 100644 testcases/kernel/controllers/kill/Makefile
>  create mode 100644 testcases/kernel/controllers/kill/kill01.c
>
> diff --git a/lib/tst_cgroup.c b/lib/tst_cgroup.c
> index 50699bc63..77575431d 100644
> --- a/lib/tst_cgroup.c
> +++ b/lib/tst_cgroup.c
> @@ -166,6 +166,7 @@ static const struct cgroup_file cgroup_ctrl_files[] = {
>         { "cgroup.controllers", NULL, 0 },
>         { "cgroup.subtree_control", NULL, 0 },
>         { "cgroup.clone_children", "cgroup.clone_children", 0 },
> +       { "cgroup.kill", NULL, 0 },
>         { }
>  };
>
> diff --git a/runtest/controllers b/runtest/controllers
> index 8d1b936bf..2f69a8ec2 100644
> --- a/runtest/controllers
> +++ b/runtest/controllers
> @@ -23,6 +23,7 @@ memcontrol01 memcontrol01
>  memcontrol02 memcontrol02
>  memcontrol03 memcontrol03
>  memcontrol04 memcontrol04
> +kill01 kill01
>
>  cgroup_fj_function_debug cgroup_fj_function.sh debug
>  cgroup_fj_function_cpuset cgroup_fj_function.sh cpuset
> diff --git a/testcases/kernel/controllers/kill/.gitignore
> b/testcases/kernel/controllers/kill/.gitignore
> new file mode 100644
> index 000000000..4f9649e27
> --- /dev/null
> +++ b/testcases/kernel/controllers/kill/.gitignore
> @@ -0,0 +1 @@
> +/kill01
> diff --git a/testcases/kernel/controllers/kill/Makefile
> b/testcases/kernel/controllers/kill/Makefile
> new file mode 100644
> index 000000000..5ea7d67db
> --- /dev/null
> +++ b/testcases/kernel/controllers/kill/Makefile
> @@ -0,0 +1,6 @@
> +# SPDX-License-Identifier: GPL-2.0-or-later
> +
> +top_srcdir             ?= ../../../..
> +
> +include $(top_srcdir)/include/mk/testcases.mk
> +include $(top_srcdir)/include/mk/generic_leaf_target.mk
> diff --git a/testcases/kernel/controllers/kill/kill01.c
> b/testcases/kernel/controllers/kill/kill01.c
> new file mode 100644
> index 000000000..aafc7ba5f
> --- /dev/null
> +++ b/testcases/kernel/controllers/kill/kill01.c
> @@ -0,0 +1,130 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2012 Christian Brauner <brauner-AT-kernel.org>
> + * Copyright (c) 2023 SUSE LLC <wegao@suse.com>
> + */
> +
> +/*\
> + * [Description]
> + *
> + * Basic cgroup kill test.
> + *
> + */
> +
> +#include <errno.h>
> +#include <linux/limits.h>
> +#include <stdbool.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <sys/types.h>
> +#include <unistd.h>
> +#include <sys/wait.h>
> +
> +#include "lapi/syscalls.h"
> +#include "tst_test.h"
> +
> +#define pid_num 100
>

My concern about defining pid_num as a fixed variable is that
the test may spend a long time on a single_cpu or slower system.
A sanity way is probably to use a dynamical number according
to the test bed available CPUs (e.g. tst_ncpus_available() + 1).



> +static struct tst_cg_group *cg_child_test_simple;
> +
> +
> +static int wait_for_pid(pid_t pid)
> +{
> +       int status, ret;
> +
> +again:
> +       ret = waitpid(pid, &status, 0);
> +       if (ret == -1) {
> +               if (errno == EINTR)
> +                       goto again;
> +
> +               return -1;
> +       }
> +
> +       if (!WIFEXITED(status))
> +               return -1;
> +
> +       return WEXITSTATUS(status);
> +}
> +
> +/*
> + * A simple process running in a sleep loop until being
> + * re-parented.
> + */
> +static int child_fn(void)
> +{
> +       int ppid = getppid();
> +
> +       while (getppid() == ppid)
> +               usleep(1000);
> +
> +       return getppid() == ppid;
>

why do we need to return the value of this comparison?
I suppose most time the child does _not_ have a chance
to get here.



> +}
> +
> +static int cg_run_nowait(const struct tst_cg_group *const cg,
> +                 int (*fn)(void))
> +{
> +       int pid;
> +
> +       pid = fork();
>

use SAFE_FORK() maybe better.



> +       if (pid == 0) {
> +               SAFE_CG_PRINTF(cg, "cgroup.procs", "%d", getpid());
> +               exit(fn());
> +       }
> +
> +       return pid;
> +}
> +
> +static int cg_wait_for_proc_count(const struct tst_cg_group *cg, int
> count)
> +{
> +       char buf[20 * pid_num] = {0};
> +       int attempts;
> +       char *ptr;
> +
> +       for (attempts = 10; attempts >= 0; attempts--) {
> +               int nr = 0;
> +
> +               SAFE_CG_READ(cg, "cgroup.procs", buf, sizeof(buf));
> +
> +               for (ptr = buf; *ptr; ptr++)
> +                       if (*ptr == '\n')
> +                               nr++;
> +
> +               if (nr >= count)
> +                       return 0;
> +
> +               usleep(100000);
>

In this loop, there is only 1 second for waiting for children ready.
So, if test on a slower/overload machine that is a bit longer than this
time,
what will happen? shouldn't we handle this as a corner case failure?



> +       }
> +
> +       return -1;
> +}
> +
> +static void run(void)
> +{
> +
> +       pid_t pids[100];
> +       int i;
> +
> +       cg_child_test_simple = tst_cg_group_mk(tst_cg, "cg_test_simple");
> +
> +       for (i = 0; i < pid_num; i++)
> +               pids[i] = cg_run_nowait(cg_child_test_simple, child_fn);
> +
> +       TST_EXP_PASS(cg_wait_for_proc_count(cg_child_test_simple,
> pid_num));
> +       SAFE_CG_PRINTF(cg_child_test_simple, "cgroup.kill", "%d", 1);
> +
> +       for (i = 0; i < pid_num; i++) {
> +               /* wait_for_pid(pids[i]); */
> +               TST_EXP_PASS_SILENT(wait_for_pid(pids[i]) == SIGKILL);
> +       }
> +
> +       cg_child_test_simple = tst_cg_group_rm(cg_child_test_simple);
> +}
> +
> +static struct tst_test test = {
> +       .test_all = run,
> +       .forks_child = 1,
> +       .max_runtime = 5,
> +       .needs_cgroup_ctrls = (const char *const []){ "memory", NULL },
> +       .needs_cgroup_ver = TST_CG_V2,
> +};
> --
> 2.35.3
>
>
> --
> Mailing list info: https://lists.linux.it/listinfo/ltp
>
>

-- 
Regards,
Li Wang


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