From: Sebastian Andrzej Siewior intel_cqm_init() holds get_online_cpus() while registerring the hotplug callbacks. cpuhp_setup_state() invokes get_online_cpus() as well. This is correct, but prevents the conversion of the hotplug locking to a percpu rwsem. Use cpuhp_setup_state_locked() to avoid the nested call. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Cc: x86@kernel.org Cc: Fenghua Yu --- arch/x86/events/intel/cqm.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) --- a/arch/x86/events/intel/cqm.c +++ b/arch/x86/events/intel/cqm.c @@ -1746,12 +1746,12 @@ static int __init intel_cqm_init(void) * Setup the hot cpu notifier once we are sure cqm * is enabled to avoid notifier leak. */ - cpuhp_setup_state(CPUHP_AP_PERF_X86_CQM_STARTING, - "perf/x86/cqm:starting", - intel_cqm_cpu_starting, NULL); - cpuhp_setup_state(CPUHP_AP_PERF_X86_CQM_ONLINE, "perf/x86/cqm:online", - NULL, intel_cqm_cpu_exit); - + cpuhp_setup_state_locked(CPUHP_AP_PERF_X86_CQM_STARTING, + "perf/x86/cqm:starting", + intel_cqm_cpu_starting, NULL); + cpuhp_setup_state_locked(CPUHP_AP_PERF_X86_CQM_ONLINE, + "perf/x86/cqm:online", + NULL, intel_cqm_cpu_exit); out: put_online_cpus();