Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754697AbaBDN3j (ORCPT ); Tue, 4 Feb 2014 08:29:39 -0500 Received: from mail4.hitachi.co.jp ([133.145.228.5]:47264 "EHLO mail4.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754675AbaBDN3f (ORCPT ); Tue, 4 Feb 2014 08:29:35 -0500 Message-ID: <52F0EB30.2070401@hitachi.com> Date: Tue, 04 Feb 2014 22:29:20 +0900 From: Masami Hiramatsu Organization: Hitachi, Ltd., Japan User-Agent: Mozilla/5.0 (Windows NT 5.2; rv:13.0) Gecko/20120614 Thunderbird/13.0.1 MIME-Version: 1.0 To: Chen Gang 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> In-Reply-To: <52F0D7F3.7000901@gmail.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 (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). > >> 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? > >>> + >>> +#endif /* CONFIG_KRETPROBES */ >>> >>> #ifdef CONFIG_KPROBES_SANITY_TEST >>> extern int init_test_probes(void); >>> @@ -379,11 +406,6 @@ void unregister_kretprobes(struct kretprobe **rps, int num); >>> void kprobe_flush_task(struct task_struct *tk); >>> void recycle_rp_inst(struct kretprobe_instance *ri, struct hlist_head *head); >>> >>> -int disable_kprobe(struct kprobe *kp); >>> -int enable_kprobe(struct kprobe *kp); >>> - >>> -void dump_kprobe(struct kprobe *kp); >>> - >>> #else /* !CONFIG_KPROBES: */ >>> >>> static inline int kprobes_built_in(void) >>> @@ -459,14 +481,6 @@ static inline int enable_kprobe(struct kprobe *kp) >>> return -ENOSYS; >>> } >>> #endif /* CONFIG_KPROBES */ >>> -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); >>> -} >>> static inline int disable_jprobe(struct jprobe *jp) >>> { >>> return disable_kprobe(&jp->kp); >>> diff --git a/kernel/kprobes.c b/kernel/kprobes.c >>> index ceeadfc..e305a81 100644 >>> --- a/kernel/kprobes.c >>> +++ b/kernel/kprobes.c >> [...] >>> @@ -1936,8 +1955,44 @@ static int __kprobes pre_handler_kretprobe(struct kprobe *p, >>> return 0; >>> } >>> >>> +void __kprobes recycle_rp_inst(struct kretprobe_instance *ri, >>> + struct hlist_head *head) >>> +{ >>> +} >>> + >>> +void __kprobes kretprobe_hash_lock(struct task_struct *tsk, >>> + struct hlist_head **head, unsigned long *flags) >>> +__acquires(hlist_lock) >>> +{ >>> +} >>> + >>> +void __kprobes kretprobe_hash_unlock(struct task_struct *tsk, >>> + unsigned long *flags) >>> +__releases(hlist_lock) >>> +{ >>> +} >>> + >> >>> +static void __kprobes kretprobe_flush_task(struct task_struct *tk) >>> +{ >>> +} >>> + >>> +static void __init init_kretprobes(void) >>> +{ >>> +} >> >> These should be macros, as I did for optprobe functions >> with !CONFIG_OPTPROBES. >> > > OK, thanks, it sounds reasonable to me. > > - For new added static functions: kretprobe_flush_task(), and > init_kretprobes() need be changed to macros > > - For extern functions: recycle_rp_inst(), kretprobe_hash_lock(), and > kretprobe_has_unlock(), need use dummy functions. > > - For original static function: pre_handler_kretprobe(), need still > use dummy function (for function pointer comparing). Right :) Thanks! > > >> Other parts looks good to me!;) >> >> Thank you! >> >> > > Thanks. > -- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com -- 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/