Messages in this thread | | | Subject | Re: kmemcheck caught read from freed memory (cfq_free_io_context) | From | Peter Zijlstra <> | Date | Wed, 02 Apr 2008 13:14:09 +0200 |
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On Wed, 2008-04-02 at 14:11 +0300, Pekka Enberg wrote: > On Wed, 2008-04-02 at 13:07 +0200, Jens Axboe wrote: > > > Makes sense, and to me Pauls analysis of the code looks totally correct > > > - there's no bug there, at least related to hlist traversal and > > > kmem_cache_free(), since we are under rcu_read_lock() and thus hold off > > > the grace for freeing. > > On Wed, Apr 2, 2008 at 2:08 PM, Peter Zijlstra <a.p.zijlstra@chello.nl> wrote: > > but what holds off the slab allocator re-issueing that same object and > > someone else writing other stuff into it? > > Nothing. So you cannot access the object at all after you've called > kmem_cache_free(). SLAB_RCU or no SLAB_RCU.
Well, you can, but you have to validate you get the object you were looking for.
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