Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755492AbbBLM07 (ORCPT ); Thu, 12 Feb 2015 07:26:59 -0500 Received: from szxga03-in.huawei.com ([119.145.14.66]:20725 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752026AbbBLM05 (ORCPT ); Thu, 12 Feb 2015 07:26:57 -0500 From: Wang Nan To: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , CC: , , , Subject: [RFC PATCH v2 00/26] Early kprobe: enable kprobes at very early booting stage. Date: Thu, 12 Feb 2015 20:17:56 +0800 Message-ID: <1423743476-11927-1-git-send-email-wangnan0@huawei.com> X-Mailer: git-send-email 1.8.4 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.107.197.247] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020205.54DC9B98.0094,ss=1,re=0.001,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 2c9447090f6abe01bfbd2de6be51da1d Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5634 Lines: 128 This is version 2 of my previous early kprobe patch series. V1 can be found from: https://lkml.org/lkml/2015/1/7/76 I haven't finished development of early kprobe. The user interface and data collection are still very weak, so you will find the weak point pointed out by Steven Rostedt (https://lkml.org/lkml/2015/1/16/430) still exists. I post this series because it has already become larger than what I've ever thought. I want to get some early review. In futher I'd like to drop patch 26/26 totally and redesign user interface. The main change of this version is to allow early probe on ftrace entry (makes early kprobe support KPROBE_ON_FTRACE). With this patch, on x86 we are able to probe at function entry if CONFIG_FTRACE is on. The basic idea is to introduce a notify chain to ftrace, and make ftrace notify kprobe when ftrace fails to modify instructions. This patch series are based on linux-next commit df9f91e. Patch 1/26 - 3/26 are already accepted, but currently they are not in linux-next repository. I resend them here only for convenience if someone want to test my code. Patch 4/26 - 8/26 are some small ftrace improvement. Patch 4 - 5 keep rec->flags unchanged when failure, make further code able to redu the failed operation. Patch 6 - 7 makes ftrace_location() can be used at early stage by sorting mcount_loc eariler. Patch 8 enables early kprobe do ftrace_make_nop() before ftrace_init(), which is important to x86 because in x86 we are unable to boost 'call' instruction. Patch 9/26 - 10/26 introduce a notify chain to ftrace and use it to notify registered subsystems to try to fix the problem before issuing ftrace_bug(). Patch 11/26 - 21/26 are core early kprobe code. Patch 11/26 introduces a kprobe_is_early() function in response to Masami Hiramatsu's comment on https://lkml.org/lkml/2015/1/13/389 that he thought comparing kprobes_initialized is hacky. There are no too much change in these patches. Patch 22/26 - 25/26 utilize the notify chain to support probe on ftrace. Patch 22 is for x86. In setup_arch(), ideal_nops is possible to change. We fix the probed nop by catching ftrace failure in ftrace_code_disable(). Patch 23/26 makes kprobe able to temporarily restore the probed instruction so ftrace is able to convert it. Patch 24/26 is the core logic which enable early kprobe on ftrace, including converting early kprobe on ftrace to normal kprobe on ftrace. Patch 25/26 is corresponding kconfig update. Patch 26/26 is a rough kernel cmdline support. The usage is similar to my V1 patch. I'd like to drop it and design a new one so let it unchanged. In my v2 patch, it is possible to proble at function entries on x86: ... ekprobe=__alloc_pages_nodemask ... and ekprobe option is able to coexist with ftrace= and ftrace_filter= options: ... ekprobe=__alloc_pages_nodemask ftrace=function \ ftrace_filter=__alloc_pages_nodemask ... In that case, events between ftrace enabled and normal kprobe fully initialized are missed in that case. Thank you! Wang Nan (26): kprobes: set kprobes_all_disarmed earlier to enable re-optimization. kprobes: makes kprobes/enabled works correctly for optimized kprobes. kprobes: x86: mark 2 bytes NOP as boostable. ftrace: don't update record flags if code modification fail. ftrace/x86: Ensure rec->flags no change when failure occures. ftrace: sort ftrace entries earlier. ftrace: allow search ftrace addr before ftrace fully inited. ftrace: enable other subsystems make ftrace nop before ftrace_init() ftrace: callchain and ftrace_bug_tryfix ftrace: x86: try to fix ftrace when ftrace_replace_code. early kprobes: introduce kprobe_is_early for futher early kprobe use. early kprobes: Add an KPROBE_FLAG_EARLY for early kprobe. early kprobes: ARM: directly modify code. early kprobes: ARM: introduce early kprobes related code area. early kprobes: x86: directly modify code. early kprobes: x86: introduce early kprobes related code area. early kprobes: introduces macros for allocing early kprobe resources. early kprobes: allows __alloc_insn_slot() from early kprobes slots. early kprobes: perhibit probing at early kprobe reserved area. early kprobes: core logic of eraly kprobes. early kprobes: add CONFIG_EARLY_KPROBES option. early kprobes: introduce arch_fix_ftrace_early_kprobe(). early kprobes: x86: arch_restore_optimized_kprobe(). early kprobes: core logic to support early kprobe on ftrace. early kprobes: introduce kconfig option to support early kprobe on ftrace. kprobes: enable 'ekprobe=' cmdline option for early kprobes. arch/Kconfig | 12 + arch/arm/include/asm/kprobes.h | 31 ++- arch/arm/kernel/vmlinux.lds.S | 2 + arch/arm/probes/kprobes/opt-arm.c | 12 +- arch/x86/include/asm/insn.h | 7 +- arch/x86/include/asm/kprobes.h | 47 +++- arch/x86/kernel/ftrace.c | 23 +- arch/x86/kernel/kprobes/core.c | 2 +- arch/x86/kernel/kprobes/opt.c | 69 +++++- arch/x86/kernel/vmlinux.lds.S | 2 + include/linux/ftrace.h | 37 ++++ include/linux/kprobes.h | 131 +++++++++++ init/main.c | 1 + kernel/kprobes.c | 451 +++++++++++++++++++++++++++++++++++++- kernel/trace/ftrace.c | 145 ++++++++++-- 15 files changed, 928 insertions(+), 44 deletions(-) -- 1.8.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/