| Message ID | 20170323152247.14733-3-svaidy@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
On Thu, Mar 23, 2017 at 4:22 PM, Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> wrote: > 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> The previous version is in linux-next already and I'm going to push it for merging shortly. > --- > drivers/cpuidle/sysfs.c | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/drivers/cpuidle/sysfs.c b/drivers/cpuidle/sysfs.c > index c5adc8c..f2c3bce 100644 > --- a/drivers/cpuidle/sysfs.c > +++ b/drivers/cpuidle/sysfs.c > @@ -615,6 +615,18 @@ int cpuidle_add_sysfs(struct cpuidle_device *dev) > struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu); > int error; > > + /* > + * Return error if cpu_device is not setup for this cpu. This > + * could happen if arch did not setup cpu_device since this > + * cpu is not in cpu_present mask and the driver did not send > + * correct cpu mask at 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; > -- > 2.9.3 >
* Rafael J. Wysocki <rafael@kernel.org> [2017-03-23 16:27:31]: > On Thu, Mar 23, 2017 at 4:22 PM, Vaidyanathan Srinivasan > <svaidy@linux.vnet.ibm.com> wrote: > > 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> > > The previous version is in linux-next already and I'm going to push it > for merging shortly. Thanks Rafael. The previous version is good for merge. --Vaidy
diff --git a/drivers/cpuidle/sysfs.c b/drivers/cpuidle/sysfs.c index c5adc8c..f2c3bce 100644 --- a/drivers/cpuidle/sysfs.c +++ b/drivers/cpuidle/sysfs.c @@ -615,6 +615,18 @@ int cpuidle_add_sysfs(struct cpuidle_device *dev) struct device *cpu_dev = get_cpu_device((unsigned long)dev->cpu); int error; + /* + * Return error if cpu_device is not setup for this cpu. This + * could happen if arch did not setup cpu_device since this + * cpu is not in cpu_present mask and the driver did not send + * correct cpu mask at 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;
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> --- drivers/cpuidle/sysfs.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)