From: Mark Rutland Date: Fri, 21 Sep 2012 10:53:41 +0000 (+0100) Subject: ARM: perf: register cpu_notifier at driver init X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=2a4961ba89ffae388a553175db51dd58ce7c39a8;p=linux-beck.git ARM: perf: register cpu_notifier at driver init The current practice of registering the cpu hotplug notifier at PMU registration time won't be safe with multiple PMUs, as we'll repeatedly attempt to register the notifier. This has the unfortunate effect of silently corrupting the notifier list, leading to boot stalling. Instead, register the notifier at init time. Its sanity checks will prevent anything bad from happening if the notifier is called before we have any PMUs registered. Signed-off-by: Mark Rutland Signed-off-by: Will Deacon --- diff --git a/arch/arm/kernel/perf_event_cpu.c b/arch/arm/kernel/perf_event_cpu.c index 02244faa5396..71c824ce0203 100644 --- a/arch/arm/kernel/perf_event_cpu.c +++ b/arch/arm/kernel/perf_event_cpu.c @@ -285,7 +285,6 @@ static int __devinit cpu_pmu_device_probe(struct platform_device *pdev) cpu_pmu = pmu; cpu_pmu->plat_device = pdev; cpu_pmu_init(cpu_pmu); - register_cpu_notifier(&cpu_pmu_hotplug_notifier); armpmu_register(cpu_pmu, cpu_pmu->name, PERF_TYPE_RAW); return 0; @@ -303,6 +302,16 @@ static struct platform_driver cpu_pmu_driver = { static int __init register_pmu_driver(void) { - return platform_driver_register(&cpu_pmu_driver); + int err; + + err = register_cpu_notifier(&cpu_pmu_hotplug_notifier); + if (err) + return err; + + err = platform_driver_register(&cpu_pmu_driver); + if (err) + unregister_cpu_notifier(&cpu_pmu_hotplug_notifier); + + return err; } device_initcall(register_pmu_driver);