Messages in this thread | | | Date | Fri, 14 Jun 2002 06:22:27 -0300 (BRT) | From | Rik van Riel <> | Subject | Re: [patch 2/16] list_head debugging |
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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/
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