From: "Jan Beulich" <JBeulich@suse.com>
To: "Peter Zijlstra" <peterz@infradead.org>,
"Ingo Molnar" <mingo@kernel.org>
Cc: <tglx@linutronix.de>, <torvalds@linux-foundation.org>,
<riel@redhat.com>, <linux-kernel@vger.kernel.org>,
<hpa@zytor.com>
Subject: Re: [tip:sched/urgent] sched/fair: Avoid using uninitialized variable in preferred_group_nid()
Date: Mon, 09 Feb 2015 11:41:19 +0000 [thread overview]
Message-ID: <54D8AAEF020000780005E2B8@mail.emea.novell.com> (raw)
In-Reply-To: <20150209113727.GS5029@twins.programming.kicks-ass.net>
>>> On 09.02.15 at 12:37, <peterz@infradead.org> wrote:
> On Mon, Feb 09, 2015 at 09:21:15AM +0100, Ingo Molnar wrote:
>> Ok, agreed, please send a separate patch to fix this.
>
> Jan, I didn't want to put your SoB on without feedback, holler and I'll
> amend it any way you like.
It's perfectly fine to add it.
Jan
> ---
> Subject: sched/numa: Avoid some pointless iterations
> From: Jan Beulich <JBeulich@suse.com>
> Date: Mon Feb 9 12:30:00 CET 2015
>
> Commit 81907478c431 ("sched/fair: Avoid using uninitialized variable
> in preferred_group_nid()") unconditionally initializes max_group with
> NODE_MASK_NONE, this means that when !max_faults (max_group didn't get
> set), we'll now continue the iteration with an empty mask.
>
> Which in turn makes the actual body of the loop go away, so we'll just
> iterate until completion; short circuit this by breaking out of the
> loop as soon as this would happen.
>
> Maybe-Signed-off-by: Jan Beulich <jbeulich@suse.com>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
> kernel/sched/fair.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -1763,6 +1763,8 @@ static int preferred_group_nid(struct ta
> }
> }
> /* Next round, evaluate the nodes within max_group. */
> + if (!max_faults)
> + break;
> nodes = max_group;
> }
> return nid;
next prev parent reply other threads:[~2015-02-09 11:41 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-23 8:25 sched/fair: avoid using uninitialized variable in preferred_group_nid() Jan Beulich
2015-01-23 9:54 ` Peter Zijlstra
2015-01-23 10:01 ` Jan Beulich
2015-01-28 14:29 ` [tip:sched/urgent] sched/fair: Avoid " tip-bot for Jan Beulich
2015-01-28 14:46 ` Jan Beulich
2015-01-28 15:37 ` Peter Zijlstra
2015-02-09 8:21 ` Ingo Molnar
2015-02-09 11:37 ` Peter Zijlstra
2015-02-09 11:41 ` Jan Beulich [this message]
2015-02-18 17:10 ` [tip:sched/core] sched/numa: Avoid some pointless iterations tip-bot for Jan Beulich
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