Re: kmemcheck caught read from freed memory (cfq_free_io_context)

[Pekka Enberg]

Hi Paul,

On Wed, Apr 2, 2008 at 1:55 PM, Paul E. McKenney
<paulmck@xxxxxxxxxxxxxxxxxx> wrote:
>  I will check this when I get back to some bandwidth -- but in the meantime,
>  does kmemcheck special-case SLAB_DESTROY_BY_RCU?  It is legal to access
>  newly-freed items in that case, as long as you did rcu_read_lock()
>  before gaining a reference to them and don't hold the reference past
>  the matching rcu_read_unlock().

No, kmemcheck is work in progress and does not know about
SLAB_DESTROY_BY_RCU yet. The reason I asked Vegard to post the warning
was because Peter, Vegard, and myself identified this particular
warning as a real problem. But yeah, kmemcheck can cause false
positives for RCU for now.

                               Pekka
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