From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4575FC433DF for ; Thu, 16 Jul 2020 17:36:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 29AE42071B for ; Thu, 16 Jul 2020 17:36:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729082AbgGPRgg (ORCPT ); Thu, 16 Jul 2020 13:36:36 -0400 Received: from mga14.intel.com ([192.55.52.115]:41307 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726986AbgGPRgg (ORCPT ); Thu, 16 Jul 2020 13:36:36 -0400 IronPort-SDR: oIn/uVRhiptHY+JRgFYAx8vOjbkPwKF1MWELHbOCXn5ErrLGaLVjdjKh/LbYfT/5zrZgpyrw2i cVLef/zb4Q0A== X-IronPort-AV: E=McAfee;i="6000,8403,9684"; a="148609836" X-IronPort-AV: E=Sophos;i="5.75,360,1589266800"; d="scan'208";a="148609836" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Jul 2020 10:36:35 -0700 IronPort-SDR: RrEqMM+RXqeRfz3aAQyUhPVJ/WdVp8OGTktWDm5+ZMajgogAQbcmX5DjY0DFkzAlqCcqt4IjSl bRAUY9wKDiug== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,360,1589266800"; d="scan'208";a="325207529" Received: from unknown (HELO localhost) ([10.249.34.156]) by FMSMGA003.fm.intel.com with ESMTP; 16 Jul 2020 10:36:30 -0700 Date: Thu, 16 Jul 2020 20:36:28 +0300 From: Jarkko Sakkinen To: Masami Hiramatsu Cc: linux-kernel@vger.kernel.org, x86@vger.kernel.org, Andi Kleen , Jessica Yu , "Naveen N. Rao" , Anil S Keshavamurthy , "David S. Miller" , Steven Rostedt , Ingo Molnar Subject: Re: [PATCH v3 3/3] kprobes: Flag out CONFIG_MODULES dependent code Message-ID: <20200716173628.GE14135@linux.intel.com> References: <20200714223239.1543716-1-jarkko.sakkinen@linux.intel.com> <20200714223239.1543716-4-jarkko.sakkinen@linux.intel.com> <20200715173524.0f21afce3574b8e8596e751e@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200715173524.0f21afce3574b8e8596e751e@kernel.org> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 15, 2020 at 05:35:24PM +0900, Masami Hiramatsu wrote: > Hi Jarkko, > > On Wed, 15 Jul 2020 01:32:29 +0300 > Jarkko Sakkinen wrote: > > > Remove CONFIG_MODULES dependency by flagging out the dependent code. This > > allows to use kprobes in a kernel without support for loadable modules, > > which could be useful for a test kernel or perhaps an embedded kernel. > > > > OK, looks good, I just have 2 comments below. > > > Cc: Andi Kleen > > Signed-off-by: Jarkko Sakkinen > > --- > > include/linux/module.h | 14 +++++++------- > > kernel/kprobes.c | 7 +++++++ > > kernel/trace/trace_kprobe.c | 16 +++++++++++++++- > > 3 files changed, 29 insertions(+), 8 deletions(-) > > > > diff --git a/include/linux/module.h b/include/linux/module.h > > index 857b84bf9e90..eaa8ad02f75c 100644 > > --- a/include/linux/module.h > > +++ b/include/linux/module.h > > @@ -290,6 +290,13 @@ extern typeof(name) __mod_##type##__##name##_device_table \ > > > > struct notifier_block; > > > > +enum module_state { > > + MODULE_STATE_LIVE, /* Normal state. */ > > + MODULE_STATE_COMING, /* Full formed, running module_init. */ > > + MODULE_STATE_GOING, /* Going away. */ > > + MODULE_STATE_UNFORMED, /* Still setting it up. */ > > +}; > > + > > #ifdef CONFIG_MODULES > > > > extern int modules_disabled; /* for sysctl */ > > @@ -305,13 +312,6 @@ struct module_use { > > struct module *source, *target; > > }; > > > > -enum module_state { > > - MODULE_STATE_LIVE, /* Normal state. */ > > - MODULE_STATE_COMING, /* Full formed, running module_init. */ > > - MODULE_STATE_GOING, /* Going away. */ > > - MODULE_STATE_UNFORMED, /* Still setting it up. */ > > -}; > > - > > struct mod_tree_node { > > struct module *mod; > > struct latch_tree_node node; > > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > > index b4f3c24cd2ef..3039df13d34e 100644 > > --- a/kernel/kprobes.c > > +++ b/kernel/kprobes.c > > @@ -2225,6 +2225,7 @@ int kprobe_add_area_blacklist(unsigned long start, unsigned long end) > > return 0; > > } > > > > +#ifdef CONFIG_MODULES > > /* Remove all symbols in given area from kprobe blacklist */ > > static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end) > > { > > @@ -2242,6 +2243,7 @@ static void kprobe_remove_ksym_blacklist(unsigned long entry) > > { > > kprobe_remove_area_blacklist(entry, entry + 1); > > } > > +#endif > > > > int __init __weak arch_populate_kprobe_blacklist(void) > > { > > @@ -2285,6 +2287,7 @@ static int __init populate_kprobe_blacklist(unsigned long *start, > > return ret ? : arch_populate_kprobe_blacklist(); > > } > > > > +#ifdef CONFIG_MODULES > > static void add_module_kprobe_blacklist(struct module *mod) > > { > > unsigned long start, end; > > @@ -2330,6 +2333,10 @@ static void remove_module_kprobe_blacklist(struct module *mod) > > kprobe_remove_area_blacklist(start, end); > > } > > } > > +#else > > +static void add_module_kprobe_blacklist(struct module *mod) {} > > +static void remove_module_kprobe_blacklist(struct module *mod) {} > > +#endif /* CONFIG_MODULES */ > > Please feel free to move the function. I would like to see; > > #ifdef CONFIG_MODULES > /* Remove all symbols in given area from kprobe blacklist */ > static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end) > { > ... > } > static void add_module_kprobe_blacklist(struct module *mod) > { > ... > } > #else > static void add_module_kprobe_blacklist(struct module *mod) {} > static void remove_module_kprobe_blacklist(struct module *mod) {} > #endif /* CONFIG_MODULES */ > > Rather than split #ifdefs. > > > > > /* Module notifier call back, checking kprobes on the module */ > > static int kprobes_module_callback(struct notifier_block *nb, > > diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c > > index 710ec6a6aa8f..7fcd1bf2d96e 100644 > > --- a/kernel/trace/trace_kprobe.c > > +++ b/kernel/trace/trace_kprobe.c > > @@ -103,8 +103,9 @@ static nokprobe_inline bool trace_kprobe_has_gone(struct trace_kprobe *tk) > > return !!(kprobe_gone(&tk->rp.kp)); > > } > > > > +#ifdef CONFIG_MODULES > > static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk, > > - struct module *mod) > > + struct module *mod) > > { > > int len = strlen(mod->name); > > const char *name = trace_kprobe_symbol(tk); > > @@ -129,6 +130,17 @@ static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk) > > > > return ret; > > } > > +#else > > +static nokprobe_inline bool trace_kprobe_within_module(struct trace_kprobe *tk, > > + struct module *mod) > > +{ > > + return false; > > +} > > +static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk) > > +{ > > + return false; > > +} > > +#endif > > > > static bool trace_kprobe_is_busy(struct dyn_event *ev) > > { > > @@ -685,10 +697,12 @@ static int trace_kprobe_module_callback(struct notifier_block *nb, > > /* Don't need to check busy - this should have gone. */ > > __unregister_trace_kprobe(tk); > > ret = __register_trace_kprobe(tk); > > +#ifdef CONFIG_MODULES > > if (ret) > > pr_warn("Failed to re-register probe %s on %s: %d\n", > > trace_probe_name(&tk->tp), > > mod->name, ret); > > +#endif > > I guess this CONFIG_MODULES is for avoiding build error according to mod->name, > if so, please use module_name(mod) macro instead of this #ifdef. > > > } > > } > > mutex_unlock(&event_mutex); > > -- > > 2.25.1 > > > > > -- > Masami Hiramatsu Thanks, agree with the remarks. /Jarkko