From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752835AbYFUSRv (ORCPT ); Sat, 21 Jun 2008 14:17:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751703AbYFUSRl (ORCPT ); Sat, 21 Jun 2008 14:17:41 -0400 Received: from ti-out-0910.google.com ([209.85.142.190]:53415 "EHLO ti-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751600AbYFUSRk (ORCPT ); Sat, 21 Jun 2008 14:17:40 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject :content-type:content-transfer-encoding; b=tchnnL6O8ycb/xboOLMEHy+wheOuapBdD0Ul8QPPQ0C/mFF+HJm+4mjqk3zJv4sgwx L46fHra1tHfk9mQm6iDIOsxDlicpoWeRrZrUTS5Gt8bfs9aGkqXZhtS1pheQb8XdQeS7 Th2+MiQ/OM6mE//WtUepIx6UetWH5Tkhdxn3w= Message-ID: <485D45AB.3000405@gmail.com> Date: Sat, 21 Jun 2008 23:47:15 +0530 From: Abhishek Sagar User-Agent: Thunderbird 2.0.0.14 (X11/20080421) MIME-Version: 1.0 To: Steven Rostedt , Ingo Molnar CC: Thomas Gleixner , LKML Subject: [PATCH 0/4] ftrace: prevent ftrace modifications while being kprobe'd Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Steven/Ingo, These patches address the problem of kprobe registration interfering with dynamic ftrace. A kprobe registered on an mcount call-site can modify that address multiple times during its duration of probing. At the same time, ftrace may simultaneously modify these locations. This could be fatal especially if ftrace modifies the call-site during a kprobe registration on it (between arch_prepare_kprobe and arch_arm_kprobe in __register_kprobe to be more precise). So as a "fix", I've disabled any updates on the mcount call-site while it's being kprobe'd. -- Regards, Abhishek Sagar