From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753652AbZLBKoQ (ORCPT ); Wed, 2 Dec 2009 05:44:16 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753590AbZLBKoP (ORCPT ); Wed, 2 Dec 2009 05:44:15 -0500 Received: from hera.kernel.org ([140.211.167.34]:44911 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751366AbZLBKoN (ORCPT ); Wed, 2 Dec 2009 05:44:13 -0500 Date: Wed, 2 Dec 2009 10:43:17 GMT From: tip-bot for Frederic Weisbecker Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, fweisbec@gmail.com, tglx@linutronix.de, mingo@elte.hu, prasad@linux.vnet.ibm.com Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, fweisbec@gmail.com, tglx@linutronix.de, prasad@linux.vnet.ibm.com, mingo@elte.hu In-Reply-To: <1259735536-9236-1-git-send-regression-fweisbec@gmail.com> References: <1259735536-9236-1-git-send-regression-fweisbec@gmail.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] hw-breakpoints: Keep track of user disabled breakpoints Message-ID: Git-Commit-ID: 1cedae72904b85462082dbcfd5190309ba37f8bd X-Mailer: tip-git-log-daemon MIME-Version: 1.0 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: 1cedae72904b85462082dbcfd5190309ba37f8bd Gitweb: http://git.kernel.org/tip/1cedae72904b85462082dbcfd5190309ba37f8bd Author: Frederic Weisbecker AuthorDate: Wed, 2 Dec 2009 07:32:16 +0100 Committer: Ingo Molnar CommitDate: Wed, 2 Dec 2009 09:59:03 +0100 hw-breakpoints: Keep track of user disabled breakpoints When we disable a breakpoint through dr7, we unregister it right away, making us lose track of its corresponding address register value. It means that the following sequence would be unsupported: - set address in dr0 - enable it through dr7 - disable it through dr7 - enable it through dr7 because we lost the address register value when we disabled the breakpoint. Don't unregister the disabled breakpoints but rather disable them. Reported-by: "K.Prasad" Signed-off-by: Frederic Weisbecker LKML-Reference: <1259735536-9236-1-git-send-regression-fweisbec@gmail.com> Signed-off-by: Ingo Molnar --- arch/x86/kernel/ptrace.c | 16 ++++++++++++---- 1 files changed, 12 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 2941b32..04d182a 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -595,7 +595,7 @@ static unsigned long ptrace_get_dr7(struct perf_event *bp[]) static struct perf_event * ptrace_modify_breakpoint(struct perf_event *bp, int len, int type, - struct task_struct *tsk) + struct task_struct *tsk, int disabled) { int err; int gen_len, gen_type; @@ -616,7 +616,7 @@ ptrace_modify_breakpoint(struct perf_event *bp, int len, int type, attr = bp->attr; attr.bp_len = gen_len; attr.bp_type = gen_type; - attr.disabled = 0; + attr.disabled = disabled; return modify_user_hw_breakpoint(bp, &attr, bp->callback, tsk); } @@ -655,13 +655,21 @@ restore: */ if (!second_pass) continue; + thread->ptrace_bps[i] = NULL; - unregister_hw_breakpoint(bp); + bp = ptrace_modify_breakpoint(bp, len, type, + tsk, 1); + if (IS_ERR(bp)) { + rc = PTR_ERR(bp); + thread->ptrace_bps[i] = NULL; + break; + } + thread->ptrace_bps[i] = bp; } continue; } - bp = ptrace_modify_breakpoint(bp, len, type, tsk); + bp = ptrace_modify_breakpoint(bp, len, type, tsk, 0); /* Incorrect bp, or we have a bug in bp API */ if (IS_ERR(bp)) {