linux-kernel - Re: [PATCH] mm, soft offline: split thp at the beginning of soft_offline

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Date:	Tue, 27 Nov 2012 13:08:38 -0800
From:	Andi Kleen <andi@...stfloor.org>
To:	Naoya Horiguchi <n-horiguchi@...jp.nec.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Tony Luck <tony.luck@...el.com>,
	Andi Kleen <andi.kleen@...el.com>,
	Wu Fengguang <fengguang.wu@...el.com>,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH] mm, soft offline: split thp at the beginning of soft_offline_page()

Naoya Horiguchi <n-horiguchi@...jp.nec.com> writes:

> When we try to soft-offline a thp tail page, put_page() is called on the
> tail page unthinkingly and VM_BUG_ON is triggered in put_compound_page().
> This patch splits thp before going into the main body of soft-offlining.

Looks good.

>
> The interface of soft-offlining is open for userspace, so this bug can
> lead to DoS attack and should be fixed immedately.

The interface is root only and root can do everything anyways, so it's
not really a security issue.

-Andi

-- 
ak@...ux.intel.com -- Speaking for myself only
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