From patchwork Tue Aug 12 03:59:21 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Miller X-Patchwork-Id: 379180 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3CBB8140082 for ; Tue, 12 Aug 2014 13:59:26 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753868AbaHLD7X (ORCPT ); Mon, 11 Aug 2014 23:59:23 -0400 Received: from shards.monkeyblade.net ([149.20.54.216]:32867 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753033AbaHLD7W (ORCPT ); Mon, 11 Aug 2014 23:59:22 -0400 Received: from localhost (74-93-104-98-Washington.hfc.comcastbusiness.net [74.93.104.98]) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 6B8005874E9 for ; Mon, 11 Aug 2014 20:59:22 -0700 (PDT) Date: Mon, 11 Aug 2014 20:59:21 -0700 (PDT) Message-Id: <20140811.205921.1409252119164411393.davem@davemloft.net> To: sparclinux@vger.kernel.org Subject: [PATCH] sparc64: Fix pcr_ops initialization and usage bugs. From: David Miller X-Mailer: Mew version 6.5 on Emacs 24.1 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.7 (shards.monkeyblade.net [149.20.54.216]); Mon, 11 Aug 2014 20:59:22 -0700 (PDT) Sender: sparclinux-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: sparclinux@vger.kernel.org Christopher reports that perf_event_print_debug() can crash in uniprocessor builds. The crash is due to pcr_ops being NULL. This happens because pcr_arch_init() is only invoked by smp_cpus_done() which only executes in SMP builds. init_hw_perf_events() is closely intertwined with pcr_ops being setup properly, therefore: 1) Call pcr_arch_init() early on from init_hw_perf_events(), instead of from smp_cpus_done(). 2) Do not hook up a PMU type if pcr_ops is NULL after pcr_arch_init(). 3) Move init_hw_perf_events to a later initcall so that it we will be sure to invoke pcr_arch_init() after all cpus are brought up. Finally, guard the one naked sequence of pcr_ops dereferences in __global_pmu_self() with an appropriate NULL check. Reported-by: Christopher Alexander Tobias Schulze Signed-off-by: David S. Miller --- This is the final version I committed to the sparc GIT tree. arch/sparc/kernel/perf_event.c | 7 +++++-- arch/sparc/kernel/process_64.c | 3 +++ arch/sparc/kernel/smp_64.c | 1 - 3 files changed, 8 insertions(+), 3 deletions(-) diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c index 8efd337..d35c490 100644 --- a/arch/sparc/kernel/perf_event.c +++ b/arch/sparc/kernel/perf_event.c @@ -1671,9 +1671,12 @@ static bool __init supported_pmu(void) static int __init init_hw_perf_events(void) { + int err; + pr_info("Performance events: "); - if (!supported_pmu()) { + err = pcr_arch_init(); + if (err || !supported_pmu()) { pr_cont("No support for PMU type '%s'\n", sparc_pmu_type); return 0; } @@ -1685,7 +1688,7 @@ static int __init init_hw_perf_events(void) return 0; } -early_initcall(init_hw_perf_events); +pure_initcall(init_hw_perf_events); void perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs) diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c index 027e099..0be7bf9 100644 --- a/arch/sparc/kernel/process_64.c +++ b/arch/sparc/kernel/process_64.c @@ -312,6 +312,9 @@ static void __global_pmu_self(int this_cpu) struct global_pmu_snapshot *pp; int i, num; + if (!pcr_ops) + return; + pp = &global_cpu_snapshot[this_cpu].pmu; num = 1; diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c index 41aa247..f7ba875 100644 --- a/arch/sparc/kernel/smp_64.c +++ b/arch/sparc/kernel/smp_64.c @@ -1383,7 +1383,6 @@ void __cpu_die(unsigned int cpu) void __init smp_cpus_done(unsigned int max_cpus) { - pcr_arch_init(); } void smp_send_reschedule(int cpu)