Input: matrix_keypad - fix race when disabling interrupts

commit ea4f7bd2aca9f68470e9aac0fc9432fd180b1fe7 upstream.

If matrix_keypad_stop() is executing and the keypad interrupt is triggered,
disable_row_irqs() may be called by both matrix_keypad_interrupt() and
matrix_keypad_stop() at the same time, causing interrupts to be disabled
twice and the keypad being "stuck" after resuming.

Take lock when setting keypad->stopped to ensure that ISR will not race
with matrix_keypad_stop() disabling interrupts.

Signed-off-by: Zhang Bo <zbsdta@126.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/input/keyboard/matrix_keypad.c b/drivers/input/keyboard/matrix_keypad.c
index e2ae657..4389ed3 100644 (file)
--- a/drivers/input/keyboard/matrix_keypad.c
+++ b/drivers/input/keyboard/matrix_keypad.c
@@ -214,8 +214,10 @@ static void matrix_keypad_stop(struct input_dev *dev)
 {
        struct matrix_keypad *keypad = input_get_drvdata(dev);
 
+       spin_lock_irq(&keypad->lock);
        keypad->stopped = true;
-       mb();
+       spin_unlock_irq(&keypad->lock);
+
        flush_work(&keypad->work.work);
        /*
         * matrix_keypad_scan() will leave IRQs enabled;