linux-kernel - Re: [PATCH] memcg: mem_cgroup_migrate() may be called with irq disabled

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Message-ID: <20160620195001.GA19775@cmpxchg.org>
Date:	Mon, 20 Jun 2016 15:50:01 -0400
From:	Johannes Weiner <hannes@...xchg.org>
To:	Tejun Heo <tj@...nel.org>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Michal Hocko <mhocko@...nel.org>,
	Vladimir Davydov <vdavydov@...tuozzo.com>,
	Linux MM <linux-mm@...ck.org>, cgroups@...r.kernel.org,
	"linux-kernel@...r.kernel.org >> Linux Kernel Mailing List" 
	<linux-kernel@...r.kernel.org>,
	Christian Borntraeger <borntraeger@...ibm.com>,
	kernel-team@...com
Subject: Re: [PATCH] memcg: mem_cgroup_migrate() may be called with irq
 disabled

On Mon, Jun 20, 2016 at 02:41:58PM -0400, Tejun Heo wrote:
> mem_cgroup_migrate() uses local_irq_disable/enable() but can be called
> with irq disabled from migrate_page_copy().  This ends up enabling irq
> while holding a irq context lock triggering the following lockdep
> warning.  Fix it by using irq_save/restore instead.

Acked-by: Johannes Weiner <hannes@...xchg.org>

Fixes: 74485cf2bc85 ("mm: migrate: consolidate mem_cgroup_migrate() calls")
CC: stable@...r.kernel.org # 4.5