From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: madhuparnabhowmik10@gmail.com, mingo@redhat.com,
peterz@infradead.org, juri.lelli@redhat.com,
vincent.guittot@linaro.org, ebiederm@xmission.com,
christian.brauner@ubuntu.com, paulmck@kernel.org,
joel@joelfernandes.org, linux-kernel@vger.kernel.org,
linux-kernel-mentees@lists.linuxfoundation.org,
frextrite@gmail.com, rcu@vger.kernel.org
Subject: Re: [PATCH] sched.h: Annotate sighand_struct with __rcu
Date: Mon, 27 Jan 2020 22:44:53 +0530 [thread overview]
Message-ID: <20200127171453.GA4002@madhuparna-HP-Notebook> (raw)
In-Reply-To: <20200127092951.GA1116@redhat.com>
On Mon, Jan 27, 2020 at 10:29:52AM +0100, Oleg Nesterov wrote:
> On 01/24, madhuparnabhowmik10@gmail.com wrote:
> >
> > --- a/include/linux/sched.h
> > +++ b/include/linux/sched.h
> > @@ -918,7 +918,7 @@ struct task_struct {
> >
> > /* Signal handlers: */
> > struct signal_struct *signal;
> > - struct sighand_struct *sighand;
> > + struct sighand_struct __rcu *sighand;
> > sigset_t blocked;
> > sigset_t real_blocked;
> > /* Restored if set_restore_sigmask() was used: */
> > diff --git a/kernel/signal.c b/kernel/signal.c
> > index bcd46f547db3..9ad8dea93dbb 100644
> > --- a/kernel/signal.c
> > +++ b/kernel/signal.c
> > @@ -1383,7 +1383,7 @@ struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
> > * must see ->sighand == NULL.
> > */
> > spin_lock_irqsave(&sighand->siglock, *flags);
> > - if (likely(sighand == tsk->sighand))
> > + if (likely(sighand == rcu_access_pointer(tsk->sighand)))
> > break;
> > spin_unlock_irqrestore(&sighand->siglock, *flags);
> > }
>
> ACK,
>
> perhaps you can also cleanup copy_sighand(). rcu_assign_pointer() makes no
> sense, we should either move it down or simply use RCU_INIT_POINTER().
>
Sure, I will do it and send a patch soon.
Thank you,
Madhuparna
> Oleg.
>
next prev parent reply other threads:[~2020-01-27 17:15 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-24 4:59 [PATCH] sched.h: Annotate sighand_struct with __rcu madhuparnabhowmik10
2020-01-25 21:41 ` Christian Brauner
2020-01-26 1:23 ` Paul E. McKenney
2020-01-27 9:29 ` Oleg Nesterov
2020-01-27 12:23 ` Christian Brauner
2020-01-27 17:14 ` Madhuparna Bhowmik [this message]
-- strict thread matches above, loose matches on Subject: below --
2020-01-23 14:53 madhuparnabhowmik10
2020-01-23 16:41 ` Paul E. McKenney
2020-01-24 4:28 ` Madhuparna Bhowmik
2020-01-22 18:11 madhuparnabhowmik10
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