Re: [PATCH 2/2] fix kill_proc_info() vs fork() theoretical race

["Paul E. McKenney" <paulmck@us.ibm.com>]

On Sat, Feb 18, 2006 at 09:19:36PM +0300, Oleg Nesterov wrote:
> "Paul E. McKenney" wrote:
> > 
> > On Fri, Feb 17, 2006 at 12:20:08AM +0300, Oleg Nesterov wrote:
> > > "Paul E. McKenney" wrote:
> > > >
> > > > The other thing to think through is tkill on a thread/process while it
> > > > is being created.  I believe that this is OK, since thread-specific
> > > > kill must target a specific thread, so does not do the traversal.
> > >
> > > Also, tkill was not converted to use rcu_read_lock yet, it still
> > > takes tasklist_lock, so I think it is safe.
> > 
> > I suspect that tkill will eventually need to avoid tasklist_lock...  ;-)
> 
> Ok, I am sending a couple of preparation patches for this.
> 
> Paul, I didn't beleive you when you started this work. Now I think
> we can avoid tasklist AND cleanup the code in many places. I am glad
> I was wrong.

And I am very glad that you are working this -- you have found some
approaches that are much better than those I would have come up with!

> Btw,
> >
> > firing off some steamroller tests on it.
> 
> Could you point me to these tests?

http://www.rdrop.com/users/paulmck/projects/steamroller/

Contributions of additional tests very welcome!

							Thanx, Paul