On Thu, Apr 13, 2017 at 02:01:42PM +0200, Thomas Gleixner wrote: > On Thu, 13 Apr 2017, Peter Zijlstra wrote: > > > > That makes my machine sad... > > [ 9.786610] work_on_cpu+0x82/0x90 > > [ 9.790404] ? __usermodehelper_disable+0x110/0x110 > > [ 9.795846] ? __acpi_processor_get_throttling+0x20/0x20 > > [ 9.801773] acpi_processor_set_throttling+0x199/0x220 > > [ 9.807506] ? trace_hardirqs_on_caller+0xfb/0x1d0 > > [ 9.812851] acpi_processor_get_throttling_ptc+0xec/0x180 > > [ 9.818876] __acpi_processor_get_throttling+0xf/0x20 > > [ 9.824511] work_for_cpu_fn+0x14/0x20 > > [ 9.828692] process_one_work+0x261/0x670 > > [ 9.833165] worker_thread+0x21b/0x3f0 > > [ 9.837348] kthread+0x108/0x140 > > [ 9.840947] ? process_one_work+0x670/0x670 > > [ 9.845611] ? kthread_create_on_node+0x40/0x40 > > [ 9.850667] ret_from_fork+0x31/0x40 > > Yuck. So the call chain is: > > acpi_processor_get_throttling() > work_on_cpu(acpi_processor_get_throttling) > > That work does: > > __acpi_processor_get_throttling() > acpi_processor_get_throttling_ptc() > acpi_processor_set_throttling() > work_on_cpu(__acpi_processor_set_throttling) > > Why the heck calls a get_throttling() function set_throttling()? I'm mildly > surprised. > > Does the delta patch below cure the problem?
Yes, aside from a compile warn. But that's disgusting... then again, you merely reintroduced this hack.
