linux-kernel - Re: [PATCH] v2 Teach RCU that idle task is not quiscent state at boot

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20090224050854.GD7173@linux.vnet.ibm.com>
Date:	Mon, 23 Feb 2009 21:08:54 -0800
From:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To:	Nick Piggin <nickpiggin@...oo.com.au>
Cc:	linux-kernel@...r.kernel.org, vegard.nossum@...il.com,
	mingo@...e.hu, stable@...nel.org, akpm@...ux-foundation.org,
	npiggin@...e.de, penberg@...helsinki.fi
Subject: Re: [PATCH] v2 Teach RCU that idle task is not quiscent state at
	boot

On Tue, Feb 24, 2009 at 03:02:56PM +1100, Nick Piggin wrote:
> On Tuesday 24 February 2009 07:43:32 Paul E. McKenney wrote:
> 
> > @@ -80,6 +81,10 @@ void wakeme_after_rcu(struct rcu_head  *head)
> >  void synchronize_rcu(void)
> >  {
> >  	struct rcu_synchronize rcu;
> > +
> > +	if (num_online_cpus() == 1)
> > +		return;  /* If UP, synchronize_rcu() is a grace period! */
> > +
> 
> Nice patch... May I just suggest a comment to say that this is
> also a correctness requirement due to the grace period holdoff
> for early boot?

Excellent point!  If Ingo reports that this actually fixes the hang that
he saw, I will add such a comment.

(And glad you like the patch!)

							Thanx, Paul
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/