During CPU online/offline testing on a large system, one of the processors got stuck after the message "bad: scheduling from the idle thread!". The problem is that acpi_cpu_soft_notify() calls acpi_bus_get_device() for all action types. CPU_STARTING and CPU_DYING do not allow the notify handlers to sleep. However, acpi_bus_get_device() can sleep in acpi_ut_acquire_mutex().
Change acpi_cpu_soft_notify() to return immediately for CPU_STARTING and CPU_DYING as they have no action in this handler. Signed-off-by: Toshi Kani <[email protected]> --- drivers/acpi/processor_driver.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c index 7f70f31..4fcbd67 100644 --- a/drivers/acpi/processor_driver.c +++ b/drivers/acpi/processor_driver.c @@ -121,6 +121,13 @@ static int acpi_cpu_soft_notify(struct notifier_block *nfb, struct acpi_processor *pr = per_cpu(processors, cpu); struct acpi_device *device; + /* + * CPU_STARTING and CPU_DYING must not sleep. Return here since + * acpi_bus_get_device() may sleep. + */ + if (action == CPU_STARTING || action == CPU_DYING) + return NOTIFY_DONE; + if (!pr || acpi_bus_get_device(pr->handle, &device)) return NOTIFY_DONE; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
