From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753305AbaBDNyS (ORCPT ); Tue, 4 Feb 2014 08:54:18 -0500 Received: from mail-pd0-f179.google.com ([209.85.192.179]:61394 "EHLO mail-pd0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751234AbaBDNyP (ORCPT ); Tue, 4 Feb 2014 08:54:15 -0500 Message-ID: <52F0F0ED.5090005@gmail.com> Date: Tue, 04 Feb 2014 21:53:49 +0800 From: Chen Gang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: Masami Hiramatsu CC: ananth@in.ibm.com, anil.s.keshavamurthy@intel.com, =?UTF-8?B?SMOldmFy?= =?UTF-8?B?ZCBTa2lubmVtb2Vu?= , David Miller , "linux-kernel@vger.kernel.org" , Hans-Christian Egtvedt , "yrl.pp-manager.tt@hitachi.com" , Ingo Molnar Subject: Re: [PATCH] kernel: kprobe: move all *kretprobe* generic implementation to CONFIG_KRETPROBES enabled area References: <52ECE5D8.6090209@gmail.com> <52EDB022.5070101@hitachi.com> <52EF8222.6030709@gmail.com> <52EFB8F4.6010207@hitachi.com> <52F04FA8.8040008@gmail.com> <52F077A1.3020701@gmail.com> <52F09404.3060502@hitachi.com> <52F0D7F3.7000901@gmail.com> <52F0EB30.2070401@hitachi.com> In-Reply-To: <52F0EB30.2070401@hitachi.com> 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 On 02/04/2014 09:29 PM, Masami Hiramatsu wrote: > (2014/02/04 21:07), Chen Gang wrote: >> On 02/04/2014 03:17 PM, Masami Hiramatsu wrote: >>> (2014/02/04 14:16), Chen Gang wrote: >>>> When CONFIG_KRETPROBES disabled, all *kretprobe* generic implementation >>>> are useless, so need move them to CONFIG_KPROBES enabled area. >>>> >>>> Now, *kretprobe* generic implementation are all implemented in 2 files: >>>> >>>> - in "include/linux/kprobes.h": >>>> >>>> move inline kretprobe*() to CONFIG_KPROBES area and dummy outside. >>>> move some *kprobe() declarations which kretprobe*() call, to front. >>>> not touch kretprobe_blacklist[] which is architecture's variable. >>>> >>>> - in "kernel/kprobes.c": >>>> >>>> move all kretprobe* to CONFIG_KPROBES area and dummy outside. >>>> define kretprobe_flush_task() to let kprobe_flush_task() call. >>>> define init_kretprobes() to let init_kprobes() call. >>>> >>>> The patch passes compiling (get "kernel/kprobes.o" and "kernel/built- >>>> in.o") under avr32 and x86_64 allmodconfig, and passes building (get >>>> bzImage and Modpost modules) under x86_64 defconfig. >>> >>> Thanks for the fix! and I have some comments below. >>> >>>> Signed-off-by: Chen Gang >>>> --- >>>> include/linux/kprobes.h | 58 +++++---- >>>> kernel/kprobes.c | 328 +++++++++++++++++++++++++++--------------------- >>>> 2 files changed, 222 insertions(+), 164 deletions(-) >>>> >>>> diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h >>>> index 925eaf2..c0d1212 100644 >>>> --- a/include/linux/kprobes.h >>>> +++ b/include/linux/kprobes.h >>>> @@ -223,10 +223,36 @@ static inline int kprobes_built_in(void) >>>> return 1; >>>> } >>>> >>>> +int disable_kprobe(struct kprobe *kp); >>>> +int enable_kprobe(struct kprobe *kp); >>>> + >>>> +void dump_kprobe(struct kprobe *kp); >>>> + >>>> +extern struct kretprobe_blackpoint kretprobe_blacklist[]; >>>> + >>>> #ifdef CONFIG_KRETPROBES >>>> extern void arch_prepare_kretprobe(struct kretprobe_instance *ri, >>>> struct pt_regs *regs); >>>> extern int arch_trampoline_kprobe(struct kprobe *p); >>>> +static inline void kretprobe_assert(struct kretprobe_instance *ri, >>>> + unsigned long orig_ret_address, unsigned long trampoline_address) >>>> +{ >>>> + if (!orig_ret_address || (orig_ret_address == trampoline_address)) { >>>> + printk(KERN_ERR >>>> + "kretprobe BUG!: Processing kretprobe %p @ %p\n", >>>> + ri->rp, ri->rp->kp.addr); >>>> + BUG(); >>>> + } >>>> +} >>>> +static inline int disable_kretprobe(struct kretprobe *rp) >>>> +{ >>>> + return disable_kprobe(&rp->kp); >>>> +} >>>> +static inline int enable_kretprobe(struct kretprobe *rp) >>>> +{ >>>> + return enable_kprobe(&rp->kp); >>>> +} >>>> + >>>> #else /* CONFIG_KRETPROBES */ >>>> static inline void arch_prepare_kretprobe(struct kretprobe *rp, >>>> struct pt_regs *regs) >>>> @@ -236,19 +262,20 @@ static inline int arch_trampoline_kprobe(struct kprobe *p) >>>> { >>>> return 0; >>>> } >>>> -#endif /* CONFIG_KRETPROBES */ >>>> - >>>> -extern struct kretprobe_blackpoint kretprobe_blacklist[]; >>>> - >>>> static inline void kretprobe_assert(struct kretprobe_instance *ri, >>>> unsigned long orig_ret_address, unsigned long trampoline_address) >>>> { >>>> - if (!orig_ret_address || (orig_ret_address == trampoline_address)) { >>>> - printk("kretprobe BUG!: Processing kretprobe %p @ %p\n", >>>> - ri->rp, ri->rp->kp.addr); >>>> - BUG(); >>>> - } >>>> } >>>> +static inline int disable_kretprobe(struct kretprobe *rp) >>>> +{ >>>> + return 0; >>>> +} >>>> +static inline int enable_kretprobe(struct kretprobe *rp) >>>> +{ >>>> + return 0; >>>> +} >>> >>> No, these should returns -EINVAL or -ENOSYS, since these are user API. >> >> OK, thanks, it sounds reasonable to me. >> >>> Anyway, I don't think those inlined functions to be changed, because >>> most of them are internal functions. If CONFIG_KRETPROBES=n, it just >>> be ignored. >>> >> >> In original implementation, if CONFIG_KRETPROBES=n, kretprobe_assert(), >> disable_kretprobe(), and enable_kretprobe() are not ignored. > > Really? where are they called? I mean, those functions do not have > any instance unless your module uses it (but that is not what the kernel > itself should help). > If what you said correct (I guess so), for me, we still need let them in CONFIG_KRETPROBES area, and without any dummy outside, just like another *kprobe* static inline functions have done in "include/linux/kprobes.h". >> >>> So, I think you don't need to change kprobes.h. >>> >> >> So "kprobes.h" still need be changed. > > Is there any concrete problem you have? > No, I just read the code, no additional really issues. Thanks. -- Chen Gang Open, share and attitude like air, water and life which God blessed