| From foo@baz Thu Dec 21 09:02:40 CET 2017 |
| From: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> |
| Date: Sun, 19 Mar 2017 00:51:59 +0530 |
| Subject: cpuidle: Validate cpu_dev in cpuidle_add_sysfs() |
| |
| From: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> |
| |
| |
| [ 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 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 <svaidy@linux.vnet.ibm.com> |
| [ rjw: Comment massage ] |
| Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
| |
| Signed-off-by: Sasha Levin <alexander.levin@verizon.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/cpuidle/sysfs.c | 12 ++++++++++++ |
| 1 file changed, 12 insertions(+) |
| |
| --- a/drivers/cpuidle/sysfs.c |
| +++ b/drivers/cpuidle/sysfs.c |
| @@ -613,6 +613,18 @@ 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; |