From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755598AbdC1NSE (ORCPT ); Tue, 28 Mar 2017 09:18:04 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:33048 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932214AbdC1Mlf (ORCPT ); Tue, 28 Mar 2017 08:41:35 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vaidyanathan Srinivasan , "Rafael J. Wysocki" Subject: [PATCH 4.10 107/111] cpuidle: Validate cpu_dev in cpuidle_add_sysfs() Date: Tue, 28 Mar 2017 14:31:33 +0200 Message-Id: <20170328122920.058187976@linuxfoundation.org> X-Mailer: git-send-email 2.12.1 In-Reply-To: <20170328122915.640228468@linuxfoundation.org> References: <20170328122915.640228468@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vaidyanathan Srinivasan commit ad0a45fd9c14feebd000b6e84189d0edff265170 upstream. If a given cpu is not in cpu_present and cpu hotplug is disabled, arch can skip setting up the cpu_dev. Arch cpuidle driver should pass correct cpu mask for registration, but failing to do so by the driver causes error to propagate and crash like this: [ 30.076045] Unable to handle kernel paging request for data at address 0x00000048 [ 30.076100] Faulting instruction address: 0xc0000000007b2f30 cpu 0x4d: Vector: 300 (Data Access) at [c000003feb18b670] pc: c0000000007b2f30: kobject_get+0x20/0x70 lr: c0000000007b3c94: kobject_add_internal+0x54/0x3f0 sp: c000003feb18b8f0 msr: 9000000000009033 dar: 48 dsisr: 40000000 current = 0xc000003fd2ed8300 paca = 0xc00000000fbab500 softe: 0 irq_happened: 0x01 pid = 1, comm = swapper/0 Linux version 4.11.0-rc2-svaidy+ (sv@sagarika) (gcc version 6.2.0 20161005 (Ubuntu 6.2.0-5ubuntu12) ) #10 SMP Sun Mar 19 00:08:09 IST 2017 enter ? for help [c000003feb18b960] c0000000007b3c94 kobject_add_internal+0x54/0x3f0 [c000003feb18b9f0] c0000000007b43a4 kobject_init_and_add+0x64/0xa0 [c000003feb18ba70] c000000000e284f4 cpuidle_add_sysfs+0xb4/0x130 [c000003feb18baf0] c000000000e26038 cpuidle_register_device+0x118/0x1c0 [c000003feb18bb30] c000000000e26c48 cpuidle_register+0x78/0x120 [c000003feb18bbc0] c00000000168fd9c powernv_processor_idle_init+0x110/0x1c4 [c000003feb18bc40] c00000000000cff8 do_one_initcall+0x68/0x1d0 [c000003feb18bd00] c0000000016242f4 kernel_init_freeable+0x280/0x360 [c000003feb18bdc0] c00000000000d864 kernel_init+0x24/0x160 [c000003feb18be30] c00000000000b4e8 ret_from_kernel_thread+0x5c/0x74 Validating cpu_dev fixes the crash and reports correct error message like: [ 30.163506] Failed to register cpuidle device for cpu136 [ 30.173329] Registration of powernv driver failed. Signed-off-by: Vaidyanathan Srinivasan [ rjw: Comment massage ] Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- drivers/cpuidle/sysfs.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) --- a/drivers/cpuidle/sysfs.c +++ b/drivers/cpuidle/sysfs.c @@ -615,6 +615,18 @@ int cpuidle_add_sysfs(struct cpuidle_dev struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu); int error; + /* + * Return if cpu_device is not setup for this CPU. + * + * This could happen if the arch did not set up cpu_device + * since this CPU is not in cpu_present mask and the + * driver did not send a correct CPU mask during registration. + * Without this check we would end up passing bogus + * value for &cpu_dev->kobj in kobject_init_and_add() + */ + if (!cpu_dev) + return -ENODEV; + kdev = kzalloc(sizeof(*kdev), GFP_KERNEL); if (!kdev) return -ENOMEM;