From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755898AbaDXK6Z (ORCPT ); Thu, 24 Apr 2014 06:58:25 -0400 Received: from terminus.zytor.com ([198.137.202.10]:52778 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755687AbaDXK6V (ORCPT ); Thu, 24 Apr 2014 06:58:21 -0400 Date: Thu, 24 Apr 2014 03:57:47 -0700 From: tip-bot for Masami Hiramatsu Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, jkosina@suse.cz, masami.hiramatsu.pt@hitachi.com, rostedt@goodmis.org, jlebon@redhat.com, tglx@linutronix.de Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, jkosina@suse.cz, masami.hiramatsu.pt@hitachi.com, rostedt@goodmis.org, jlebon@redhat.com, tglx@linutronix.de In-Reply-To: <20140417081651.26341.10593.stgit@ltc230.yrl.intra.hitachi.co.jp> References: <20140417081651.26341.10593.stgit@ltc230.yrl.intra.hitachi.co.jp> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/kprobes] kprobes/x86: Allow to handle reentered kprobe on single-stepping Git-Commit-ID: 6a5022a56ac37da7bffece043331a101ed0040b1 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 6a5022a56ac37da7bffece043331a101ed0040b1 Gitweb: http://git.kernel.org/tip/6a5022a56ac37da7bffece043331a101ed0040b1 Author: Masami Hiramatsu AuthorDate: Thu, 17 Apr 2014 17:16:51 +0900 Committer: Ingo Molnar CommitDate: Thu, 24 Apr 2014 10:02:55 +0200 kprobes/x86: Allow to handle reentered kprobe on single-stepping Since the NMI handlers(e.g. perf) can interrupt in the single stepping (or preparing the single stepping, do_debug etc.), we should consider a kprobe is hit in the NMI handler. Even in that case, the kprobe is allowed to be reentered as same as the kprobes hit in kprobe handlers (KPROBE_HIT_ACTIVE or KPROBE_HIT_SSDONE). The real issue will happen when a kprobe hit while another reentered kprobe is processing (KPROBE_REENTER), because we already consumed a saved-area for the previous kprobe. Signed-off-by: Masami Hiramatsu Reviewed-by: Steven Rostedt Cc: Jiri Kosina Cc: Jonathan Lebon Link: http://lkml.kernel.org/r/20140417081651.26341.10593.stgit@ltc230.yrl.intra.hitachi.co.jp Signed-off-by: Ingo Molnar --- arch/x86/kernel/kprobes/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 61b17dc..da7bdaa 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -531,10 +531,11 @@ reenter_kprobe(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb switch (kcb->kprobe_status) { case KPROBE_HIT_SSDONE: case KPROBE_HIT_ACTIVE: + case KPROBE_HIT_SS: kprobes_inc_nmissed_count(p); setup_singlestep(p, regs, kcb, 1); break; - case KPROBE_HIT_SS: + case KPROBE_REENTER: /* A probe has been hit in the codepath leading up to, or just * after, single-stepping of a probed instruction. This entire * codepath should strictly reside in .kprobes.text section.