When CONFIG_PREEMPT=y, the following warning shows up: BUG: using smp_processor_id() in preemptible [00000000] code: swapper/0/1 caller is pseries_processor_idle_init+0x58/0x21c
This warning shows up because preemption cannot occur when using get_paca(), otherwise the paca_struct it points to may be the wrong one just after. For this reason, preemption needs to be disabled before lppaca_shared_proc(get_lppaca()). Signed-off-by: Victor Aoqui <vict...@linux.vnet.ibm.com> --- drivers/cpuidle/cpuidle-pseries.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/cpuidle/cpuidle-pseries.c b/drivers/cpuidle/cpuidle-pseries.c index e9b3853..d6dda8c 100644 --- a/drivers/cpuidle/cpuidle-pseries.c +++ b/drivers/cpuidle/cpuidle-pseries.c @@ -233,12 +233,16 @@ static int pseries_cpuidle_driver_init(void) */ static int pseries_idle_probe(void) { + int retval; if (cpuidle_disable != IDLE_NO_OVERRIDE) return -ENODEV; if (firmware_has_feature(FW_FEATURE_SPLPAR)) { - if (lppaca_shared_proc(get_lppaca())) { + preempt_disable(); + retval = lppaca_shared_proc(get_lppaca()); + preempt_enable(); + if (retval) { cpuidle_state_table = shared_states; max_idle_state = ARRAY_SIZE(shared_states); } else { -- 1.8.3.1