From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754597Ab1JMKMF (ORCPT ); Thu, 13 Oct 2011 06:12:05 -0400 Received: from e4.ny.us.ibm.com ([32.97.182.144]:53482 "EHLO e4.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754581Ab1JMKME (ORCPT ); Thu, 13 Oct 2011 06:12:04 -0400 Date: Thu, 13 Oct 2011 15:42:04 +0530 From: Ananth N Mavinakayanahalli To: Maneesh Soni Cc: ralf@linux-mips.org, linux-kernel@vger.kernel.org, linux-mips@linux-mips.org, david.daney@cavium.com, kamensky@cisco.com Subject: Re: [PATCH] MIPS Kprobes: Support branch instructions probing Message-ID: <20111013101204.GB19054@in.ibm.com> Reply-To: ananth@in.ibm.com References: <20111013090749.GB16761@cisco.com> <20111013094137.GA19054@in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20111013094137.GA19054@in.ibm.com> User-Agent: Mutt/1.5.17 (2007-11-01) x-cbid: 11101310-3534-0000-0000-0000009D643C Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 13, 2011 at 03:11:37PM +0530, Ananth N Mavinakayanahalli wrote: > On Thu, Oct 13, 2011 at 02:37:49PM +0530, Maneesh Soni wrote: > > ... > > I know nothing of MIPS internals, but... > > > static int __kprobes kprobe_handler(struct pt_regs *regs) > > @@ -239,8 +531,13 @@ static int __kprobes kprobe_handler(struct pt_regs *regs) > > save_previous_kprobe(kcb); > > set_current_kprobe(p, regs, kcb); > > kprobes_inc_nmissed_count(p); > > - prepare_singlestep(p, regs); > > + prepare_singlestep(p, regs, kcb); > > kcb->kprobe_status = KPROBE_REENTER; > > + if (kcb->flags & SKIP_DELAYSLOT) { > > + resume_execution(p, regs, kcb); > > + restore_previous_kprobe(kcb); > > + preempt_enable_no_resched(); > > + } > > return 1; > > } else { > > if (addr->word != breakpoint_insn.word) { > > @@ -284,8 +581,15 @@ static int __kprobes kprobe_handler(struct pt_regs *regs) > > } > > > > ss_probe: > > - prepare_singlestep(p, regs); > > - kcb->kprobe_status = KPROBE_HIT_SS; > > + prepare_singlestep(p, regs, kcb); > > + if (kcb->flags & SKIP_DELAYSLOT) { > > + kcb->kprobe_status = KPROBE_HIT_SSDONE; > > + if (p->post_handler) > > + p->post_handler(p, regs, 0); > > + resume_execution(p, regs, kcb); > > You are missing a preempt_disable_no_resched() here. Oops! I meant preempt_enable_no_resched(). Ananth