Date: Fri, 30 Nov 2012 00:00:43 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lin Feng <linfeng@cn.fujitsu.com>, viro@zeniv.linux.org.uk, bcrl@kvack.org,
        mhocko@suse.cz, hughd@google.com, cl@linux.com, mgorman@suse.de,
        minchan@kernel.org, isimatu.yasuaki@jp.fujitsu.com,
        laijs@cn.fujitsu.com, wency@cn.fujitsu.com, tangchen@cn.fujitsu.com,
        linux-fsdevel@vger.kernel.org, linux-aio@kvack.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [BUG REPORT] [mm-hotplug, aio] aio ring_pages can't be offlined
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On Fri, 30 Nov 2012 16:13:16 +0900 Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:

> > What about futexes?
> >
> 
> IIUC, futex's key is now a pair of (mm,address) or (inode, pgoff).
> Then, get_user_page() in futex.c will release the page by put_page().
> 'struct page' is just touched by get_futex_key() to obtain page->mapping info.

Ah yes, that page is unpinned before syscall return.

	grep -rl get_user_pages .

Gad.

These should be audited.  The great majority will be simple and OK,
but drivers/media, drivers/infiniband and net/rds could be problematic.
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