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Date: Mon, 9 Jul 2012 15:59:52 +0530
From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>, Peter Zijlstra <peterz@infradead.org>,
        Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
        Anton Arapov <anton@redhat.com>, Hugh Dickins <hughd@google.com>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 3/5] uprobes: kill
 write_opcode()->lock_page(new_page)
Message-ID: <20120709102952.GE32393@linux.vnet.ibm.com>
Reply-To: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
References: <20120624145936.GA23269@redhat.com>
 <20120624150035.GC23277@redhat.com>
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* Oleg Nesterov <oleg@redhat.com> [2012-06-24 17:00:35]:

> write_opcode() does lock_page(new_page) for no reason. Nobody can
> see this page until __replace_page() exposes it under ptl lock, and
> we do nothing with this page after pte_unmap_unlock().
> 
> If nothing else, the similar code in do_wp_page() doesn't lock the
> new page for page_add_new_anon_rmap/set_pte_at_notify.
> 
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>

Acked-by: Srikar Dronamraju<srikar@linux.vnet.ibm.com>