From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754539Ab2G3OLn (ORCPT ); Mon, 30 Jul 2012 10:11:43 -0400 Received: from terminus.zytor.com ([198.137.202.10]:45556 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754401Ab2G3OLk (ORCPT ); Mon, 30 Jul 2012 10:11:40 -0400 Date: Mon, 30 Jul 2012 07:11:25 -0700 From: tip-bot for Oleg Nesterov Message-ID: Cc: linux-kernel@vger.kernel.org, anton@redhat.com, hpa@zytor.com, mingo@kernel.org, srikar@linux.vnet.ibm.com, oleg@redhat.com, tglx@linutronix.de Reply-To: mingo@kernel.org, hpa@zytor.com, anton@redhat.com, linux-kernel@vger.kernel.org, srikar@linux.vnet.ibm.com, tglx@linutronix.de, oleg@redhat.com In-Reply-To: <20120729182218.GA20315@redhat.com> References: <20120729182218.GA20315@redhat.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] uprobes: Kill write_opcode()->lock_page(new_page) Git-Commit-ID: 089ba999dc881a7549d97c55ac9e0052d061867d X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.6 (terminus.zytor.com [127.0.0.1]); Mon, 30 Jul 2012 07:11:31 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 089ba999dc881a7549d97c55ac9e0052d061867d Gitweb: http://git.kernel.org/tip/089ba999dc881a7549d97c55ac9e0052d061867d Author: Oleg Nesterov AuthorDate: Sun, 29 Jul 2012 20:22:18 +0200 Committer: Ingo Molnar CommitDate: Mon, 30 Jul 2012 11:27:19 +0200 uprobes: Kill write_opcode()->lock_page(new_page) 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 Acked-by: Srikar Dronamraju Cc: Anton Arapov Cc: Srikar Dronamraju Link: http://lkml.kernel.org/r/20120729182218.GA20315@redhat.com Signed-off-by: Ingo Molnar --- kernel/events/uprobes.c | 2 -- 1 files changed, 0 insertions(+), 2 deletions(-) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 6fda799..23c562b7 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -239,9 +239,7 @@ retry: if (ret) goto unlock_out; - lock_page(new_page); ret = __replace_page(vma, vaddr, old_page, new_page); - unlock_page(new_page); unlock_out: unlock_page(old_page);