Re: [RFC][PATCH 0/5] tracing: Add new file system tracefs

[Al Viro <viro@ZenIV.linux.org.uk>]

On Thu, Jan 22, 2015 at 07:00:07AM +0800, Greg Kroah-Hartman wrote:
> On Wed, Jan 21, 2015 at 12:19:53PM -0500, Steven Rostedt wrote:
> > 
> > There has been complaints that tracing is tied too much to debugfs,
> > as there are systems that would like to perform tracing, but do
> > not mount debugfs for security reasons. That is because any subsystem
> > may use debugfs for debugging, and these interfaces are not always
> > tested for security.
> > 
> > Creating a new tracefs that the tracing directory will now be attached
> > to allows system admins the ability to access the tracing directory
> > without the need to mount debugfs.
> 
> Yeah!
> 
> Any chance you can use kernfs as your "basis" for this filesystem
> instead of having to roll all of your own functions?  I'm slowly working
> on moving debugfs to it, and it should save a lot of code there, as well
> as fixing some "problems" we have in debugfs file lifetimes when things
> are removed from the system.

I would recommend against that - kernfs is overburdened by their need to
accomodate cgroup weirdness.  IMO it's not a good model for anything, other
than an anti-hard-drugs poster ("don't shoot that shit, or you might end up
hallucinating _this_").