[PATCH v4] kernel: add kcov code coverage

[Kirill A. Shutemov]

On Tue, Jan 19, 2016 at 01:55:43PM +0100, Dmitry Vyukov wrote:
> >> +static int __init kcov_init(void)
> >> +{
> >> +     if (!debugfs_create_file("kcov", 0666, NULL, NULL, &kcov_fops)) {
> >
> > Why 0666? May be 0600?.
> 
> The idea is that it can be useful to fuzz-test under a normal user as well.
> This file is also guarded by debugfs mount permissions. Usually it is mounted
> as 0700, so normal users can't get access to it.
> However if one wants to fuzz-test under a normal user, he could mount
> debugfs as 0777 and get access to this file.
> 
> I am not very strong about this, though. If you say, I will change it to 0600.
> I open this file as root at the moment. And we can change it back
> if/when we better understand a potential use case.

I think it's safer to make it 0600. It's up to system administrator to
change permissions, if he wants give this capability to mortals.

-- 
 Kirill A. Shutemov