[CRIU] [PATCH] report the potential selinux problem if mmap_seized() fails

[Cyrill Gorcunov]

On Wed, Apr 22, 2015 at 12:39:49PM +0300, Pavel Emelyanov wrote:
> On 04/21/2015 08:16 PM, Oleg Nesterov wrote:
> > selinux can deny mmap(PROT_WRITE | PROT_EXEC) and in this case it is
> > not clear why CRIU fails, "Can't allocate memory for parasite blob"
> > doesn't tell too much. Add a pr_warn() hint for the user.
> > 
> > Signed-off-by: Oleg Nesterov <oleg at redhat.com>
> > ---
> >  arch/x86/crtools.c |   11 +++++++++--
> >  1 files changed, 9 insertions(+), 2 deletions(-)
> > 
> > diff --git a/arch/x86/crtools.c b/arch/x86/crtools.c
> > index 02ce2e5..06d824a 100644
> > --- a/arch/x86/crtools.c
> > +++ b/arch/x86/crtools.c
> > @@ -445,8 +445,15 @@ void *mmap_seized(struct parasite_ctl *ctl,
> >  
> >  	err = syscall_seized(ctl, __NR_mmap, &map,
> >  			(unsigned long)addr, length, prot, flags, fd, offset);
> > -	if (err < 0 || map > TASK_SIZE)
> > -		map = 0;
> > +	if (err < 0)
> > +		return NULL;
> > +
> > +	if (IS_ERR_VALUE(map)) {
> 
> The IS_ERR_VALUE is only a subset of > TASK_SIZE, so this change is
> not 100% correct. In particular the map > TASK_SIZE check was added 
> for ARM and is important there.

It's not, it's x86 specific code