Re: [PATCH 3/7] sched: Use dl_bw_of() under RCU read lock

From: Kirill Tkhai
Date: Sat Sep 20 2014 - 15:25:47 EST


On 20.09.2014 22:57, Peter Zijlstra wrote:
> On Sat, Sep 20, 2014 at 08:51:28PM +0400, Kirill Tkhai wrote:
>> From: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
>>
>> dl_bw_of() dereferences rq->rd which has to have RCU read lock held.
>> Probability of use-after-free and memory corruption aren't zero here.
>>
>
> Additionally we might want to add something like:
> lockdep_assert_held_rcu() and put that in dl_bw_of() and other such
> places.

Should we change (not now, in general) RCU-related pointers to use
rcu_dereference() to have unlocked RCU warnings in dmesg? To catch
a problems like that.

This may make code worse readable though.

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