Re: [tip:sched/urgent] sched/fair: Avoid using uninitialized variable in preferred_group_nid()
From: Jan Beulich
Date: Mon Feb 09 2015 - 06:41:28 EST
>>> On 09.02.15 at 12:37, <peterz@xxxxxxxxxxxxx> 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.
> Subject: sched/numa: Avoid some pointless iterations
> From: Jan Beulich <JBeulich@xxxxxxxx>
> 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@xxxxxxxx>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
> 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;
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/