Re: [patch 2/16] list_head debugging
Rik van Riel (riel@conectiva.com.br)
Fri, 14 Jun 2002 06:22:27 -0300 (BRT)
On Mon, 10 Jun 2002, Jan Harkes wrote:
> On Mon, Jun 03, 2002 at 05:41:39PM -0300, Rik van Riel wrote:
> > > We've had this before, and it breaks some code that removes items from
> > > lists as follows,
> >
> > Such code is probably not SMP safe anyway.
>
> Where are you coming from with that comment?
>
> down(&semaphore);
>
> list_for_each(p, list)
> if (condition)
> list_del(p);
>
> up(&semaphore);
>
> Should be completely SMP safe,
Not if 'p' comes from the slab cache.
In that case 'p' can be re-allocated on another CPU
before we dereference ->next ...
regards,
Rik
--
Bravely reimplemented by the knights who say "NIH".
http://www.surriel.com/ http://distro.conectiva.com/
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/