From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Brown Subject: Missing "unregister_cpu_notifier" in powernow-k8.c Date: Wed, 24 Nov 2010 11:28:01 +1100 Message-ID: <20101124112801.78830fba@notabene.brown> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: Sender: cpufreq-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: x86@kernel.org, cpufreq@vger.kernel.org, Dave Jones Cc: linux-kernel@vger.kernel.org Hi, (hope I got the right addressees above....) I appears that when powernow-k8 find that No compatible ACPI _PSS objects found. and suggests Try again with latest BIOS. it fails the module load, but does not unregister the cpu_notifier that was registered in powernowk8_init This ends up leaving freed memory on the cpu notifier list for some other poor module (e.g. md/raid5) to come along and trip over. The following might be a partial fix, but I suspect there is probably other clean-up that is needed. ( https://bugzilla.novell.com/show_bug.cgi?id=655215 has full dmesg traces). Thanks, NeilBrown diff --git a/arch/x86/kernel/cpu/cpufreq/powernow-k8.c b/arch/x86/kernel/cpu/cpufreq/powernow-k8.c index 491977b..812778c 100644 --- a/arch/x86/kernel/cpu/cpufreq/powernow-k8.c +++ b/arch/x86/kernel/cpu/cpufreq/powernow-k8.c @@ -1537,6 +1537,7 @@ static struct notifier_block cpb_nb = { static int __cpuinit powernowk8_init(void) { unsigned int i, supported_cpus = 0, cpu; + int rv; for_each_online_cpu(i) { int rc; @@ -1574,7 +1575,10 @@ static int __cpuinit powernowk8_init(void) (cpb_enabled ? "on" : "off")); } - return cpufreq_register_driver(&cpufreq_amd64_driver); + rv = cpufreq_register_driver(&cpufreq_amd64_driver); + if (rv < 0 && boot_cpu_has(X86_FEATURE_CPB)) + unregister_cpu_notifier(&cpb_nb); + return rv; } /* driver entry point for term */