[CRIU] [PATCH] check: try to call clone with CLONE_NEWPID and CLONE_PARENT

[Andrew Vagin]

Adrian, could you apply this patch and try to execute "criu check"?

Thanks,
Andrew

On Tue, Jun 30, 2015 at 02:12:07PM +0300, Andrey Vagin wrote:
> This combination was forbidden in 3.12
> commit 40a0d32d1eaffe6aac7324ca92604b6b3977eb0e :
> "fork: unify and tighten up CLONE_NEWUSER/CLONE_NEWPID checks"
> 
> and then it was permited again in 3.13:
> commit 1f7f4dde5c945f41a7abc2285be43d918029ecc5
> fork:  Allow CLONE_PARENT after setns(CLONE_NEWPID)
> 
> Cc: Adrian Reber <adrian at lisas.de>
> Signed-off-by: Andrey Vagin <avagin at openvz.org>
> ---
>  cr-check.c | 28 ++++++++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
> 
> diff --git a/cr-check.c b/cr-check.c
> index 7cf796a..bf1b729 100644
> --- a/cr-check.c
> +++ b/cr-check.c
> @@ -688,6 +688,33 @@ static int check_fdinfo_lock(void)
>  	return 0;
>  }
>  
> +struct clone_arg {
> +	/*
> +	 * Reserve some space for clone() to locate arguments
> +	 * and retcode in this place
> +	 */
> +	char stack[128] __attribute__((aligned (8)));
> +	char stack_ptr[0];
> +};
> +
> +static int clone_cb(void *_arg) {
> +	exit(0);
> +}
> +
> +static int check_clone_parent_vs_pid()
> +{
> +	struct clone_arg ca;
> +	pid_t pid;
> +
> +	pid = clone(clone_cb, ca.stack_ptr, CLONE_NEWPID | CLONE_PARENT, &ca);
> +	if (pid < 0) {
> +		pr_err("CLONE_PARENT | CLONE_NEWPID don't work together\n");
> +		return -1;
> +	}
> +
> +	return 0;
> +}
> +
>  static int (*chk_feature)(void);
>  
>  int cr_check(void)
> @@ -741,6 +768,7 @@ int cr_check(void)
>  	ret |= check_mnt_id();
>  	ret |= check_aio_remap();
>  	ret |= check_fdinfo_lock();
> +	ret |= check_clone_parent_vs_pid();
>  
>  out:
>  	if (!ret)
> -- 
> 2.1.0
>