From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751064AbaFJKuN (ORCPT ); Tue, 10 Jun 2014 06:50:13 -0400 Received: from mail4.hitachi.co.jp ([133.145.228.5]:33773 "EHLO mail4.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750716AbaFJKuL (ORCPT ); Tue, 10 Jun 2014 06:50:11 -0400 Subject: [PATCH ftrace/core 0/2] ftrace, kprobes: Introduce IPMODIFY flag for ftrace_ops to detect conflicts From: Masami Hiramatsu To: Steven Rostedt , Josh Poimboeuf Cc: Ingo Molnar , Namhyung Kim , Linux Kernel Mailing List , Ananth N Mavinakayanahalli Date: Tue, 10 Jun 2014 10:50:01 +0000 Message-ID: <20140610105001.8732.93502.stgit@kbuild-fedora.novalocal> User-Agent: StGit/0.17-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Here is a pair of patches which introduces IPMODIFY flag for ftrace_ops to detect conflicts of ftrace users who can modify regs->ip in their handler. Currently, only kprobes can change the regs->ip in the handler, but recently kpatch is also want to change it. Moreover, since the ftrace itself exported to modules, it might be considerable senario. Here we talked on github. https://github.com/dynup/kpatch/issues/47 To protect modified regs-ip from each other, this series introduces FTRACE_OPS_FL_IPMODIFY flag and ftrace now ensures the flag can be set on each function entry location. If there is someone who already reserve regs->ip on target function entry, ftrace_set_filter_ip or register_ftrace_function will return -EBUSY. Users must handle that. At this point, all kprobes will reserve regs->ip, since jprobe requires it. Thank you, --- Masami Hiramatsu (2): ftrace: Simplify ftrace_hash_disable/enable path in ftrace_hash_move ftrace, kprobes: Support IPMODIFY flag to find IP modify conflict Documentation/trace/ftrace.txt | 5 + include/linux/ftrace.h | 10 ++- kernel/kprobes.c | 2 - kernel/trace/ftrace.c | 152 ++++++++++++++++++++++++++++++++++------ 4 files changed, 143 insertions(+), 26 deletions(-) --