Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755832AbXLSDey (ORCPT ); Tue, 18 Dec 2007 22:34:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751941AbXLSDeq (ORCPT ); Tue, 18 Dec 2007 22:34:46 -0500 Received: from mx1.redhat.com ([66.187.233.31]:57612 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751299AbXLSDeq (ORCPT ); Tue, 18 Dec 2007 22:34:46 -0500 Message-ID: <476890CC.1020100@redhat.com> Date: Tue, 18 Dec 2007 22:32:28 -0500 From: Masami Hiramatsu User-Agent: Thunderbird 2.0.0.9 (X11/20071115) MIME-Version: 1.0 To: Ananth N Mavinakayanahalli , Jim Keniston , Ingo Molnar CC: Roland McGrath , prasanna@in.ibm.com, anil.s.keshavamurthy@intel.com, davem@davemloft.net, Harvey Harrison , systemtap-ml , LKML , Arjan van de Ven Subject: Re: [PATCH 1/2] x86: fix kprobe_handler reenable preemption References: <4768555A.3000604@redhat.com> In-Reply-To: <4768555A.3000604@redhat.com> X-Enigmail-Version: 0.95.5 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1674 Lines: 57 Hi Masami Hiramatsu wrote: > Fix a preemption bug in kprobe_handler(). It has to call preempt_enable() > before returning. > I think this is critical on preemptive kernel. Sorry, this patch has a mistake. > > Signed-off-by: Masami Hiramatsu > --- > arch/x86/kernel/kprobes.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > Index: b/arch/x86/kernel/kprobes.c > =================================================================== > --- a/arch/x86/kernel/kprobes.c 2007-12-18 12:51:00.000000000 -0500 > +++ b/arch/x86/kernel/kprobes.c 2007-12-18 12:53:38.000000000 -0500 > @@ -467,7 +467,8 @@ > arch_disarm_kprobe(p); > regs->ip = (unsigned long)p->addr; > reset_current_kprobe(); > - return 1; > + ret = 1; > + goto no_kprobe; > #endif > } > /* We have reentered the kprobe_handler(), since > @@ -481,7 +482,7 @@ > kprobes_inc_nmissed_count(p); > prepare_singlestep(p, regs); > kcb->kprobe_status = KPROBE_REENTER; > - return 1; > + ret = 1; Here, "return 1;" is correct. After single step is done, preemption is enabled in post_kprobe_handler(). > } else { > if (*addr != BREAKPOINT_INSTRUCTION) { > /* The breakpoint instruction was removed by > -- Masami Hiramatsu Software Engineer Hitachi Computer Products (America) Inc. Software Solutions Division e-mail: mhiramat@redhat.com, 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/