tick_check_preferred() calls cpumask_equal() even if curdev->cpumask == newdev->cpumask. Fix it. Caught with CONFIG_DEBUG_BITMAP: [ 0.079109] Call trace: [ 0.079124] __bitmap_check_params+0x144/0x250 [ 0.079161] tick_check_replacement+0x1a4/0x320 [ 0.079203] tick_check_new_device+0x50/0x110 [ 0.079237] clockevents_register_device+0x74/0x1c0 [ 0.079268] dummy_timer_starting_cpu+0x6c/0x80 [ 0.079310] cpuhp_invoke_callback+0x104/0x20c [ 0.079353] cpuhp_invoke_callback_range+0x70/0xf0 [ 0.079401] notify_cpu_starting+0xac/0xcc [ 0.079434] secondary_start_kernel+0xe4/0x154 [ 0.079471] __secondary_switched+0xa0/0xa4 [ 0.079516] ---[ end trace 0000000000000000 ]--- [ 0.079542] b1: ffffbfec4703b890 [ 0.079553] b2: ffffbfec4703b890 [ 0.079566] b3: 0 [ 0.079576] nbits: 256 [ 0.079588] start: 0 [ 0.079598] off: 0 [ 0.079609] Bitmap: parameters check failed [ 0.079619] include/linux/bitmap.h [419]: bitmap_equal Signed-off-by: Yury Norov <yury.norov@xxxxxxxxx> --- kernel/time/tick-common.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c index 46789356f856..fdd5ae1a074b 100644 --- a/kernel/time/tick-common.c +++ b/kernel/time/tick-common.c @@ -316,9 +316,13 @@ static bool tick_check_preferred(struct clock_event_device *curdev, * Use the higher rated one, but prefer a CPU local device with a lower * rating than a non-CPU local device */ - return !curdev || - newdev->rating > curdev->rating || - !cpumask_equal(curdev->cpumask, newdev->cpumask); + if (!curdev || newdev->rating > curdev->rating) + return true; + + if (newdev->cpumask == curdev->cpumask) + return false; + + return !cpumask_equal(curdev->cpumask, newdev->cpumask); } /* -- 2.34.1
