Re: [PATCH] debugobjects: Move printk out of db lock critical sections

From: Sergey Senozhatsky
Date: Thu Dec 13 2018 - 04:00:36 EST

On (12/13/18 05:54), Dmitry Safonov wrote:
> > I thought about it for a second, but couldn't figure out if this race
> > was real.
> >
> > E.g. uart case - if there are two paths which concurrently free and
> > access debug object, then the same race condition should exist for
> > the xmit.buf page. debug object's lifespan should be the same as the
> > lifespan of, ummm, whatever the thing that debug object is attached
> > to? I'm surely missing something here.
> I think the point of debugobjects is to reduce the damage caused
> by an improper life-time of objects.
> 1. alloc_page()
> 2. dynamically allocate a workqueue on a new page
> 3. schedule some work
> 4. until the work has run free_page()

Hmm, if we free() that page then __debug_check_no_obj_freed() should ->fixup
all ODEBUG_STATE_ACTIVE objects first. Maybe we are talking about different