From: Peter Zijlstra <peterz@infradead.org>
To: Kirill Tkhai <tkhai@yandex.ru>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
Kirill Tkhai <ktkhai@parallels.com>
Subject: Re: [PATCH 3/7] sched: Use dl_bw_of() under RCU read lock
Date: Sat, 20 Sep 2014 21:32:12 +0200 [thread overview]
Message-ID: <20140920193212.GY2832@worktop.localdomain> (raw)
In-Reply-To: <541DD4B3.7080400@yandex.ru>
On Sat, Sep 20, 2014 at 11:25:39PM +0400, Kirill Tkhai wrote:
> 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@parallels.com>
> >>
> >> 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.
Possibly, we should probably use rcu_assign_pointer() and
rcu_dereference() on rq->rd. Sometimes you can avoid that if you're
playing games with static objects, but I don't think that is true here.
next prev parent reply other threads:[~2014-09-20 19:32 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-20 16:51 [PATCH 1/7] sched/fair: Remove duplicate code from can_migrate_task() Kirill Tkhai
2014-09-20 16:51 ` [PATCH 2/7] sched: Fix picking a task switching on other cpu (__ARCH_WANT_UNLOCKED_CTXSW) Kirill Tkhai
2014-09-20 18:33 ` Peter Zijlstra
2014-09-20 18:54 ` Peter Zijlstra
2014-09-20 20:09 ` Kirill Tkhai
2014-09-20 20:19 ` Kirill Tkhai
2014-09-20 19:03 ` Peter Zijlstra
2014-09-20 16:51 ` [PATCH 3/7] sched: Use dl_bw_of() under RCU read lock Kirill Tkhai
2014-09-20 18:57 ` Peter Zijlstra
2014-09-20 19:25 ` Kirill Tkhai
2014-09-20 19:32 ` Peter Zijlstra [this message]
2014-09-20 16:51 ` [PATCH 4/7] sched: cleanup: Rename out_unlock to out_free_new_mask Kirill Tkhai
2014-09-20 16:51 ` [PATCH 5/7] sched: Use rq->rd in sched_setaffinity() under RCU read lock Kirill Tkhai
2014-09-20 18:59 ` Peter Zijlstra
2014-09-20 19:05 ` Kirill Tkhai
2014-09-20 19:18 ` Peter Zijlstra
2014-09-20 19:21 ` Kirill Tkhai
2014-09-20 16:51 ` [PATCH 6/7] sched: Delete rq::skip_clock_update == -1 Kirill Tkhai
2014-09-20 19:01 ` Peter Zijlstra
2014-09-21 4:37 ` Mike Galbraith
2014-09-20 16:51 ` [PATCH 7/7] sched/rt: Use resched_curr() in task_tick_rt() Kirill Tkhai
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