On Tue, 07 May 2024, Hans de Goede wrote: > Some triggers call led_trigger_event() from their activate() callback > to initialize the brightness of the LED for which the trigger is being > activated. > > In order for the LEDs initial state to be set correctly this requires that > the led_trigger_event() call uses the new version of trigger->led_cdevs, > which has the new LED. > > AFAICT led_trigger_event() will always use the new version when it is > running on the same CPU as where the list_add_tail_rcu() call was made, > which is why the missing synchronize_rcu() has not lead to bug reports. > But if activate() is pre-empted, sleeps or uses a worker then > the led_trigger_event() call may run on another CPU which may still use > the old trigger->led_cdevs list. > > Add a synchronize_rcu() call to ensure that any led_trigger_event() calls > done from activate() always use the new list. > > Triggers using led_trigger_event() from their activate() callback are: > net/bluetooth/leds.c, net/rfkill/core.c and drivers/tty/vt/keyboard.c. > > Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> > --- > drivers/leds/led-triggers.c | 7 +++++++ > 1 file changed, 7 insertions(+) Looks like there have been a few changes to led_trigger_set() since this was authored. Please rebase and resubmit. Thanks. -- Lee Jones [李琼斯]
