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

[Adrian Reber]

On Tue, Jun 30, 2015 at 03:48:25PM +0300, Andrew Vagin wrote:
> Adrian, could you apply this patch and try to execute "criu check"?

Error (cr-check.c:711): CLONE_PARENT | CLONE_NEWPID don't work together

This means my kernel needs patching, right?

		Adrian

> 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
> >