Re: [PATCH] memcg: Fix race condition in memcg_check_events() with this_cpu usage

KAMEZAWA Hiroyuki
2011-09-26T00:44:19Z

On Fri, 23 Sep 2011 20:54:42 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> From: Steven Rostedt <srostedt@redhat.com>
>
> The code in memcg_check_events() calls this_cpu_read() on
> different variables without disabling preemption, and can cause
> the calculations to be done from two different CPU variables.
>
> Disable preemption throughout the check to keep apples and oranges
> from becoming a mixed drink.
>
> [ Added this_cpu to __this_cpu conversion by Johannes ]
>
> Cc: Greg Thelen <gthelen@google.com>
> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Christoph Lameter <cl@linux.com>
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> Link: http://lkml.kernel.org/r/20110919212641.015320989@goodmis.org

Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

Andrew, could you pick this up ?