From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
linux-kernel@vger.kernel.org, tglx@linutronix.de,
Anna-Maria Gleixner <anna-maria@linutronix.de>
Subject: Re: [PATCH] kernel/signal: Remove no longer required irqsave/restore
Date: Fri, 4 May 2018 10:52:41 -0700 [thread overview]
Message-ID: <20180504175241.GT26088@linux.vnet.ibm.com> (raw)
In-Reply-To: <876043e3xb.fsf@xmission.com>
On Fri, May 04, 2018 at 12:17:20PM -0500, Eric W. Biederman wrote:
> Sebastian Andrzej Siewior <bigeasy@linutronix.de> writes:
>
> > On 2018-05-04 11:59:08 [-0500], Eric W. Biederman wrote:
> >> Sebastian Andrzej Siewior <bigeasy@linutronix.de> writes:
> >> > From: Anna-Maria Gleixner <anna-maria@linutronix.de>
> > …
> >> > This long-term fix has been made in commit 4abf91047cf ("rtmutex: Make >
> >> > wait_lock irq safe") for different reason.
> >>
> >> Which tree has this change been made in? I am not finding the commit
> >> you mention above in Linus's tree.
> >
> > I'm sorry, it should have been commit b4abf91047cf ("rtmutex: Make
> > wait_lock irq safe").
>
> Can you fix that in your patch description and can you also up the
> description of rcu_read_unlock?
>
> If we don't need to jump through hoops it looks very reasonable to
> remove this unnecessary logic. But we should fix the description
> in rcu_read_unlock that still says we need these hoops.
The hoops are still required for rcu_read_lock(), otherwise you
get deadlocks between the scheduler and RCU in PREEMPT=y kernels.
What happens with this patch (if I understand it correctly) is that the
signal code now uses a different way of jumping through the hoops.
But the hoops are still jumped through.
Thanx, Paul
next prev parent reply other threads:[~2018-05-04 17:51 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-04 14:40 [PATCH] kernel/signal: Remove no longer required irqsave/restore Sebastian Andrzej Siewior
2018-05-04 16:59 ` Eric W. Biederman
2018-05-04 17:04 ` Sebastian Andrzej Siewior
2018-05-04 17:17 ` Eric W. Biederman
2018-05-04 17:52 ` Paul E. McKenney [this message]
2018-05-04 19:03 ` Eric W. Biederman
2018-05-04 19:45 ` Paul E. McKenney
2018-05-04 20:08 ` Eric W. Biederman
2018-05-04 20:37 ` Paul E. McKenney
2018-05-05 4:38 ` Eric W. Biederman
2018-05-05 5:25 ` Paul E. McKenney
2018-05-05 5:56 ` Thomas Gleixner
2018-05-08 13:42 ` Anna-Maria Gleixner
2018-05-08 14:53 ` Paul E. McKenney
2018-05-08 15:49 ` Anna-Maria Gleixner
2018-05-08 16:53 ` Paul E. McKenney
2018-06-07 20:21 ` [tip:core/urgent] signal: " tip-bot for Anna-Maria Gleixner
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