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From: Peter Zijlstra <peterz@infradead.org>
To: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Bruno Wolff III <bruno@wolff.to>, Josh Boyer <jwboyer@redhat.com>,
	"mingo@redhat.com" <mingo@redhat.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: Scheduler regression from caffcdd8d27ba78730d5540396ce72ad022aff2c
Date: Thu, 17 Jul 2014 11:04:52 +0200	[thread overview]
Message-ID: <20140717090452.GH19379@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <53C79013.1020808@arm.com>

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On Thu, Jul 17, 2014 at 10:57:55AM +0200, Dietmar Eggemann wrote:
> There is also the possibility that the memory for sched_group sg is not
> (completely) zeroed out:
> 
>   sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
> 			GFP_KERNEL, cpu_to_node(j));
> 
> 
>   struct sched_group {
> 	...
> 	 * NOTE: this field is variable length. (Allocated dynamically
> 	 * by attaching extra space to the end of the structure,
> 	 * depending on how many CPUs the kernel has booted up with)
> 	 */
> 	unsigned long cpumask[0];

well kZalloc should Zero the entire allocated size, and the specified
size very much includes the cpumask size as per:
  sizeof(struct sched_group) + cpumask_size()

But yeah, I'm also a bit puzzled why this goes bang. Makes we worry we
scribble it somewhere or so.

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  reply	other threads:[~2014-07-17  9:05 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-16 14:55 Scheduler regression from caffcdd8d27ba78730d5540396ce72ad022aff2c Bruno Wolff III
2014-07-16 15:17 ` Josh Boyer
2014-07-16 19:17   ` Dietmar Eggemann
2014-07-16 19:54     ` Bruno Wolff III
2014-07-16 23:18       ` Dietmar Eggemann
2014-07-17  3:09         ` Bruno Wolff III
2014-07-17  8:57           ` Dietmar Eggemann
2014-07-17  9:04             ` Peter Zijlstra [this message]
2014-07-17 11:23               ` Dietmar Eggemann
2014-07-17 12:35                 ` Peter Zijlstra
2014-07-18  5:34                   ` Bruno Wolff III
2014-07-18  9:28                     ` Dietmar Eggemann
2014-07-18 12:09                       ` Bruno Wolff III
2014-07-18 10:16                     ` Peter Zijlstra
2014-07-18 13:01                       ` Bruno Wolff III
2014-07-18 14:16                         ` Dietmar Eggemann
2014-07-18 14:16                         ` Peter Zijlstra
2014-07-18 14:50                           ` Peter Zijlstra
2014-07-18 16:16                             ` Peter Zijlstra
2014-07-21 16:35                               ` Bruno Wolff III
2014-07-21 16:52                                 ` Peter Zijlstra
2014-07-22  9:47                                   ` Peter Zijlstra
2014-07-22 10:38                                     ` Peter Zijlstra
2014-07-22 12:10                                       ` Bruno Wolff III
2014-07-22 13:03                                         ` Peter Zijlstra
2014-07-22 13:26                                           ` Peter Zijlstra
2014-07-22 13:35                                             ` Peter Zijlstra
2014-07-22 14:09                                               ` Bruno Wolff III
2014-07-22 14:18                                                 ` Peter Zijlstra
2014-07-23  1:37                                                   ` Bruno Wolff III
2014-07-23  6:51                                                     ` Peter Zijlstra
2014-07-22 17:05                                               ` H. Peter Anvin
2014-07-23 15:11                                               ` Peter Zijlstra
2014-07-23 15:12                                                 ` H. Peter Anvin
2014-07-24  1:45                                                 ` Bruno Wolff III
2014-07-23 15:39                                               ` [tip:x86/urgent] x86, cpu: Fix cache topology for early P4-SMT tip-bot for Peter Zijlstra
2014-07-22 12:12                                     ` Scheduler regression from caffcdd8d27ba78730d5540396ce72ad022aff2c Dietmar Eggemann
2014-07-22 12:57                                     ` Bruno Wolff III
2014-07-28  8:28                                     ` [tip:sched/core] sched: Robustify topology setup tip-bot for Peter Zijlstra
2014-07-17 16:36             ` Scheduler regression from caffcdd8d27ba78730d5540396ce72ad022aff2c Bruno Wolff III
2014-07-17 18:43               ` Dietmar Eggemann
2014-07-17 18:54                 ` Bruno Wolff III
2014-07-17  4:21         ` Bruno Wolff III
2014-07-17  4:28     ` Bruno Wolff III

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