klp_task_patch: was: [RFC PATCH v2 17/18] livepatch: change to a per-task consistency model

[Jiri Kosina]

On Wed, 4 May 2016, Petr Mladek wrote:

> > +
> > +		if (unlikely(klp_patch_pending(current)))
> > +			klp_patch_task(current);
> >  	}
> 
> Some more ideas from the world of crazy races. I was shaking my head
> if this was safe or not.
> 
> The problem might be if the task get rescheduled between the check
> for the pending stuff 

The code in question is running with preemption disabled.

> or inside the klp_patch_task() function. 

We must make sure that this function doesn't go to sleep. It's only used 
to clear the task_struct flag anyway.

-- 
Jiri Kosina
SUSE Labs