From: Thomas Gleixner tglx@linutronix.de
commit d364847eed890211444ad74496bb549f838c6018 upstream.
Chris Wilson reported splats from running the thermal throttling workqueue callback on offlined CPUs. The problem is that that callback should not even run on offlined CPUs but it happens nevertheless because the offlining callback thermal_throttle_offline() does not symmetrically undo the setup work done in its onlining counterpart. IOW,
1. The thermal interrupt vector should be masked out before ...
2. ... cancelling any pending work synchronously so that no new work is enqueued anymore.
Do those things and fix the issue properly.
[ bp: Write commit message. ]
Fixes: f6656208f04e ("x86/mce/therm_throt: Optimize notifications of thermal throttle") Reported-by: Chris Wilson chris@chris-wilson.co.uk Tested-by: Pandruvada, Srinivas srinivas.pandruvada@linux.intel.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Signed-off-by: Borislav Petkov bp@suse.de Link: https://lkml.kernel.org/r/158120068234.18291.7938335950259651295@skylake-alp... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/kernel/cpu/mce/therm_throt.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
--- a/arch/x86/kernel/cpu/mce/therm_throt.c +++ b/arch/x86/kernel/cpu/mce/therm_throt.c @@ -486,9 +486,14 @@ static int thermal_throttle_offline(unsi { struct thermal_state *state = &per_cpu(thermal_state, cpu); struct device *dev = get_cpu_device(cpu); + u32 l;
- cancel_delayed_work(&state->package_throttle.therm_work); - cancel_delayed_work(&state->core_throttle.therm_work); + /* Mask the thermal vector before draining evtl. pending work */ + l = apic_read(APIC_LVTTHMR); + apic_write(APIC_LVTTHMR, l | APIC_LVT_MASKED); + + cancel_delayed_work_sync(&state->package_throttle.therm_work); + cancel_delayed_work_sync(&state->core_throttle.therm_work);
state->package_throttle.rate_control_active = false; state->core_throttle.rate_control_active = false;