From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-bl2nam02on0108.outbound.protection.outlook.com ([104.47.38.108]:10166 "EHLO NAM02-BL2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1031888AbeCAPXd (ORCPT ); Thu, 1 Mar 2018 10:23:33 -0500 From: Sasha Levin To: "stable@vger.kernel.org" , "stable-commits@vger.kernel.org" CC: Vaidyanathan Srinivasan , "Rafael J . Wysocki" , Sasha Levin Subject: [added to the 4.1 stable tree] cpuidle: Validate cpu_dev in cpuidle_add_sysfs() Date: Thu, 1 Mar 2018 15:22:38 +0000 Message-ID: <20180301152116.1486-18-alexander.levin@microsoft.com> References: <20180301152116.1486-1-alexander.levin@microsoft.com> In-Reply-To: <20180301152116.1486-1-alexander.levin@microsoft.com> Content-Language: en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org List-ID: From: Vaidyanathan Srinivasan This patch has been added to the 4.1 stable tree. If you have any objections, please let us know. =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D [ Upstream commit ad0a45fd9c14feebd000b6e84189d0edff265170 ] 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 0= x00000048 [ 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 =3D 0xc000003fd2ed8300 paca =3D 0xc00000000fbab500 softe: 0 irq_happened: 0x01 pid =3D 1, comm =3D 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: Sasha Levin --- drivers/cpuidle/sysfs.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/cpuidle/sysfs.c b/drivers/cpuidle/sysfs.c index 832a2c3f01ff..9e98a5fbbc1d 100644 --- a/drivers/cpuidle/sysfs.c +++ b/drivers/cpuidle/sysfs.c @@ -613,6 +613,18 @@ int cpuidle_add_sysfs(struct cpuidle_device *dev) struct device *cpu_dev =3D get_cpu_device((unsigned long)dev->cpu); int error; =20 + /* + * 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 =3D kzalloc(sizeof(*kdev), GFP_KERNEL); if (!kdev) return -ENOMEM; --=20 2.14.1