[PATCH 4.9 20/86] Input: matrix_keypad - fix race when disabling interrupts

Greg Kroah-Hartman
2018-03-16T15:22:43Z

From: Zhang Bo <zbsdta@126.com>

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>
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/input/keyboard/matrix_keypad.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/input/keyboard/matrix_keypad.c
+++ b/drivers/input/keyboard/matrix_keypad.c
@@ -216,8 +216,10 @@ static void matrix_keypad_stop(struct in
{
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;