From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753290Ab3KNLgz (ORCPT ); Thu, 14 Nov 2013 06:36:55 -0500 Received: from mail4.hitachi.co.jp ([133.145.228.5]:51867 "EHLO mail4.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752801Ab3KNLgx (ORCPT ); Thu, 14 Nov 2013 06:36:53 -0500 Message-ID: <5284B5D2.70206@hitachi.com> Date: Thu, 14 Nov 2013 20:36:50 +0900 From: Masami Hiramatsu Organization: Hitachi, Ltd., Japan User-Agent: Mozilla/5.0 (Windows NT 5.2; rv:13.0) Gecko/20120614 Thunderbird/13.0.1 MIME-Version: 1.0 To: Petr Mladek Cc: Steven Rostedt , Frederic Weisbecker , "Paul E. McKenney" , Jiri Kosina , linux-kernel@vger.kernel.org, x86@kernel.org Subject: Re: [PATCH v3 4/8] x86: speed up int3-based patching using direct write References: <1384425686-21018-1-git-send-email-pmladek@suse.cz> <1384425686-21018-5-git-send-email-pmladek@suse.cz> In-Reply-To: <1384425686-21018-5-git-send-email-pmladek@suse.cz> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (2013/11/14 19:41), Petr Mladek wrote: > @@ -837,7 +882,7 @@ static void recover_iter(struct text_poke_bp_iter *iterator, > } > > /* Finally, put back the first byte from the old code */ > - err = text_poke(addr, old_opcode, sizeof(bp_int3)); > + err = text_poke_part(addr, old_opcode, sizeof(bp_int3)); > /* we can not continue if the interrupt is still there */ > BUG_ON(err); > } > @@ -865,7 +910,9 @@ static void recover_iter(struct text_poke_bp_iter *iterator, > * It is a bit more paranoid than text_poke_bp because it checks the actual > * code before patching. This is a good practice proposed by the ftrace code. > * > - * Note: This function must be called under text_mutex. > + * Note: This function must be called under text_mutex. Also the caller is > + * responsible for making the patched code read-write, for example using > + * set_kernel_text_rw() and set_all_modules_text_rw() OK, I got the reason why we can do it. But if so, we should change all existing caller of text_poke_bp() to call it in this patch, or they must fail at this point. Thank you, -- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com