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Re: Preemption-safe kprobe-booster(Re: [PATCH]kprobe booster for IA64)
- From: Keshavamurthy Anil S <anil dot s dot keshavamurthy at intel dot com>
- To: Masami Hiramatsu <masami dot hiramatsu dot pt at hitachi dot com>
- Cc: Keshavamurthy Anil S <anil dot s dot keshavamurthy at intel dot com>, Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, SystemTAP <systemtap at sources dot redhat dot com>, Yumiko Sugita <yumiko dot sugita dot yf at hitachi dot com>, Satoshi Oshima <soshima at redhat dot com>, Hideo Aoki <haoki at redhat dot com>, Prasanna S Panchamukhi <prasanna at in dot ibm dot com>, Jim Keniston <jkenisto at us dot ibm dot com>
- Date: Fri, 14 Jul 2006 11:26:28 -0700
- Subject: Re: Preemption-safe kprobe-booster(Re: [PATCH]kprobe booster for IA64)
- References: <4485223C.8090109@sdl.hitachi.co.jp> <20060628190541.A13874@unix-os.sc.intel.com> <44AAF207.7090908@sdl.hitachi.co.jp> <44B4952D.9010603@hitachi.com> <20060712010122.A30357@unix-os.sc.intel.com> <44B62D9D.20303@hitachi.com>
- Reply-to: Keshavamurthy Anil S <anil dot s dot keshavamurthy at intel dot com>
On Thu, Jul 13, 2006 at 08:25:17PM +0900, Masami Hiramatsu wrote:
> Hi, Anil
> Thank you for precise advice.
>
> Keshavamurthy Anil S wrote:
> > On Wed, Jul 12, 2006 at 03:22:37PM +0900, Masami Hiramatsu wrote:
> Now, we are searching for other good solutions against this problem.
>
> Anyway, I'd like to disable booster when CONFIG_PREEMPT is defined
> until this problem is solved. I attached the patch to this mail.
> Please review it.
>
--Comment here please
/* Booster probe is not support for preemptable kernel */
> +#ifdef CONFIG_PREEMPT
^^^^^^ Should be #ifndef
> + if (p->ainsn.boostable == 1 && !p->post_handler){
> /* Boost up -- we can execute copied instructions directly */
> reset_current_kprobe();
> regs->eip = (unsigned long)p->ainsn.insn;
> preempt_enable_no_resched();
> return 1;
> }
> +#endif
> prepare_singlestep(p, regs);
> kcb->kprobe_status = KPROBE_HIT_SS;
> return 1;
Also you may want to do the same thing for kretprobe booster.
Thanks,
Anil