Re: [RFC v2 1/4] kunit: Add 'kunit_shutdown' option

[Daniel Latypov <dlatypov@google.com>]

On Thu, Apr 29, 2021 at 1:51 PM Brendan Higgins
<brendanhiggins@google.com> wrote:
>
> From: David Gow <davidgow@google.com>
>
> Add a new kernel command-line option, 'kunit_shutdown', which allows the
> user to specify that the kernel poweroff, halt, or reboot after
> completing all KUnit tests; this is very handy for running KUnit tests
> on UML or a VM so that the UML/VM process exits cleanly immediately
> after running all tests without needing a special initramfs.
>
> Signed-off-by: David Gow <davidgow@google.com>
> Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
> Reviewed-by: Stephen Boyd <sboyd@kernel.org>

Tested-By: Daniel Latypov <dlatypov@google.com>

Testing this out, I think this also helps fix coverage on UML.
I used to have to hack in something like this:

diff --git a/arch/um/os-Linux/util.c b/arch/um/os-Linux/util.c
index 07327425d06e..e13763faedd9 100644
--- a/arch/um/os-Linux/util.c
+++ b/arch/um/os-Linux/util.c
@@ -146,7 +146,7 @@ void os_dump_core(void)
        while ((pid = waitpid(-1, NULL, WNOHANG | __WALL)) > 0)
                os_kill_ptraced_process(pid, 0);

-       uml_abort();
+       exit(127);
 }

 void um_early_printk(const char *s, unsigned int n)

And afaict, this patch removes the need to do so.
(But I made a few mistakes when initially trying to test that out, so
I'm not 100% certain I didn't make another).

> ---
>  lib/kunit/executor.c                | 20 ++++++++++++++++++++
>  tools/testing/kunit/kunit_kernel.py |  2 +-
>  tools/testing/kunit/kunit_parser.py |  2 +-
>  3 files changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/lib/kunit/executor.c b/lib/kunit/executor.c
> index 15832ed446685..7db619624437c 100644
> --- a/lib/kunit/executor.c
> +++ b/lib/kunit/executor.c
> @@ -1,5 +1,6 @@
>  // SPDX-License-Identifier: GPL-2.0
>
> +#include <linux/reboot.h>
>  #include <kunit/test.h>
>  #include <linux/glob.h>
>  #include <linux/moduleparam.h>
> @@ -18,6 +19,9 @@ module_param(filter_glob, charp, 0);
>  MODULE_PARM_DESC(filter_glob,
>                 "Filter which KUnit test suites run at boot-time, e.g. list*");
>
> +static char *kunit_shutdown;
> +core_param(kunit_shutdown, kunit_shutdown, charp, 0644);
> +
>  static struct kunit_suite * const *
>  kunit_filter_subsuite(struct kunit_suite * const * const subsuite)
>  {
> @@ -82,6 +86,20 @@ static struct suite_set kunit_filter_suites(void)
>         return filtered;
>  }
>
> +static void kunit_handle_shutdown(void)
> +{
> +       if (!kunit_shutdown)
> +               return;
> +
> +       if (!strcmp(kunit_shutdown, "poweroff"))
> +               kernel_power_off();
> +       else if (!strcmp(kunit_shutdown, "halt"))
> +               kernel_halt();
> +       else if (!strcmp(kunit_shutdown, "reboot"))
> +               kernel_restart(NULL);
> +
> +}
> +
>  static void kunit_print_tap_header(struct suite_set *suite_set)
>  {
>         struct kunit_suite * const * const *suites, * const *subsuite;
> @@ -112,6 +130,8 @@ int kunit_run_all_tests(void)
>                 kfree(suite_set.start);
>         }
>
> +       kunit_handle_shutdown();
> +
>         return 0;
>  }
>
> diff --git a/tools/testing/kunit/kunit_kernel.py b/tools/testing/kunit/kunit_kernel.py
> index f309a33256cd3..7d5b77967d48f 100644
> --- a/tools/testing/kunit/kunit_kernel.py
> +++ b/tools/testing/kunit/kunit_kernel.py
> @@ -206,7 +206,7 @@ class LinuxSourceTree(object):
>         def run_kernel(self, args=None, build_dir='', filter_glob='', timeout=None) -> Iterator[str]:
>                 if not args:
>                         args = []
> -               args.extend(['mem=1G', 'console=tty'])
> +               args.extend(['mem=1G', 'console=tty','kunit_shutdown=halt'])
>                 if filter_glob:
>                         args.append('kunit.filter_glob='+filter_glob)
>                 self._ops.linux_bin(args, timeout, build_dir)
> diff --git a/tools/testing/kunit/kunit_parser.py b/tools/testing/kunit/kunit_parser.py
> index e8bcc139702e2..8d8d4d70b39dd 100644
> --- a/tools/testing/kunit/kunit_parser.py
> +++ b/tools/testing/kunit/kunit_parser.py
> @@ -49,7 +49,7 @@ class TestStatus(Enum):
>
>  kunit_start_re = re.compile(r'TAP version [0-9]+$')
>  kunit_end_re = re.compile('(List of all partitions:|'
> -                         'Kernel panic - not syncing: VFS:)')
> +                         'Kernel panic - not syncing: VFS:|reboot: System halted)')
>
>  def isolate_kunit_output(kernel_output) -> Iterator[str]:
>         started = False
> --
> 2.31.1.498.g6c1eba8ee3d-goog
>