From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762457AbZEOIrt (ORCPT ); Fri, 15 May 2009 04:47:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758592AbZEOIon (ORCPT ); Fri, 15 May 2009 04:44:43 -0400 Received: from hera.kernel.org ([140.211.167.34]:57257 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761690AbZEOIol (ORCPT ); Fri, 15 May 2009 04:44:41 -0400 Date: Fri, 15 May 2009 08:44:01 GMT From: tip-bot for Ingo Molnar To: linux-tip-commits@vger.kernel.org Cc: linux-kernel@vger.kernel.org, paulus@samba.org, hpa@zytor.com, mingo@redhat.com, a.p.zijlstra@chello.nl, tglx@linutronix.de, cjashfor@linux.vnet.ibm.com, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, paulus@samba.org, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, tglx@linutronix.de, cjashfor@linux.vnet.ibm.com, mingo@elte.hu In-Reply-To: References: Subject: [tip:perfcounters/core] perf_counter: x86: Protect against infinite loops in intel_pmu_handle_irq() Message-ID: Git-Commit-ID: 9029a5e3801f1cc7cdaab80169d82427acf928d8 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Fri, 15 May 2009 08:44:03 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 9029a5e3801f1cc7cdaab80169d82427acf928d8 Gitweb: http://git.kernel.org/tip/9029a5e3801f1cc7cdaab80169d82427acf928d8 Author: Ingo Molnar AuthorDate: Fri, 15 May 2009 08:26:20 +0200 Committer: Ingo Molnar CommitDate: Fri, 15 May 2009 09:47:06 +0200 perf_counter: x86: Protect against infinite loops in intel_pmu_handle_irq() intel_pmu_handle_irq() can lock up in an infinite loop if the hardware does not allow the acking of irqs. Alas, this happened in testing so make this robust and emit a warning if it happens in the future. Also, clean up the IRQ handlers a bit. [ Impact: improve perfcounter irq/nmi handling robustness ] Acked-by: Peter Zijlstra Cc: Paul Mackerras Cc: Corey Ashford LKML-Reference: Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_counter.c | 25 ++++++++++++++++++------- 1 files changed, 18 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c index 46a82d1..5a7f718 100644 --- a/arch/x86/kernel/cpu/perf_counter.c +++ b/arch/x86/kernel/cpu/perf_counter.c @@ -722,9 +722,13 @@ static void intel_pmu_save_and_restart(struct perf_counter *counter) */ static int intel_pmu_handle_irq(struct pt_regs *regs, int nmi) { - int bit, cpu = smp_processor_id(); + struct cpu_hw_counters *cpuc; + struct cpu_hw_counters; + int bit, cpu, loops; u64 ack, status; - struct cpu_hw_counters *cpuc = &per_cpu(cpu_hw_counters, cpu); + + cpu = smp_processor_id(); + cpuc = &per_cpu(cpu_hw_counters, cpu); perf_disable(); status = intel_pmu_get_status(); @@ -733,7 +737,13 @@ static int intel_pmu_handle_irq(struct pt_regs *regs, int nmi) return 0; } + loops = 0; again: + if (++loops > 100) { + WARN_ONCE(1, "perfcounters: irq loop stuck!\n"); + return 1; + } + inc_irq_stat(apic_perf_irqs); ack = status; for_each_bit(bit, (unsigned long *)&status, X86_PMC_IDX_MAX) { @@ -765,13 +775,14 @@ again: static int amd_pmu_handle_irq(struct pt_regs *regs, int nmi) { - int cpu = smp_processor_id(); - struct cpu_hw_counters *cpuc = &per_cpu(cpu_hw_counters, cpu); - u64 val; - int handled = 0; + int cpu, idx, throttle = 0, handled = 0; + struct cpu_hw_counters *cpuc; struct perf_counter *counter; struct hw_perf_counter *hwc; - int idx, throttle = 0; + u64 val; + + cpu = smp_processor_id(); + cpuc = &per_cpu(cpu_hw_counters, cpu); if (++cpuc->interrupts == PERFMON_MAX_INTERRUPTS) { throttle = 1;