On Mon, 2014-04-14 at 17:11 +0200, Igor Mammedov wrote: > acpi_processor_add() assumes that present at boot CPUs > are always onlined, it is not so if a CPU failed to become > onlined. As result acpi_processor_add() will mark such CPU > device as onlined in sysfs and following attempts to > online/offline it using /sys/device/system/cpu/cpuX/online > attribute will fail. > > Do not poke into device internals in acpi_processor_add() > and touch "struct device { .offline }" attribute, since > for CPUs onlined at boot it's set by: > topology_init() -> arch_register_cpu() -> register_cpu() > before ACPI device tree is parsed, and for hotplugged > CPUs it's set when userspace onlines CPU via sysfs. > > Signed-off-by: Igor Mammedov <imammedo@xxxxxxxxxx> > --- > v2: > - fix regression in v1 leading to NULL pointer dereference > on CPU unplug, do not remove "pr->dev = dev;" > --- > drivers/acpi/acpi_processor.c | 1 - > 1 files changed, 0 insertions(+), 1 deletions(-) > > diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c > index c29c2c3..42d66f8 100644 > --- a/drivers/acpi/acpi_processor.c > +++ b/drivers/acpi/acpi_processor.c > @@ -404,7 +404,6 @@ static int acpi_processor_add(struct acpi_device *device, > goto err; > > pr->dev = dev; > - dev->offline = pr->flags.need_hotplug_init; IIRC, this change was necessary to handle the case when maxcpus=X is specified at boot. In this case, excessive CPU's dev->offline needs to be set to 1. Can you verify this? Thanks, -Toshi -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html