From bc0207a5461169eba13e9421bd7632399b72e3ab Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Thu, 16 Jun 2016 11:02:41 +0200 Subject: [PATCH] gpiolib: avoid uninitialized data in gpio kfifo gcc reports a theoretical case for returning uninitialized data in the kfifo when a GPIO interrupt happens and neither GPIOEVENT_REQUEST_RISING_EDGE nor GPIOEVENT_REQUEST_FALLING_EDGE are set: drivers/gpio/gpiolib.c: In function 'lineevent_irq_thread': drivers/gpio/gpiolib.c:683:87: error: 'ge.id' may be used uninitialized in this function [-Werror=maybe-uninitialized] This case should not happen, but to be on the safe side, let's return from the irq handler without adding data to the FIFO to ensure we can never leak stack data to user space. Signed-off-by: Arnd Bergmann Fixes: 61f922db7221 ("gpio: userspace ABI for reading GPIO line events") Signed-off-by: Linus Walleij --- drivers/gpio/gpiolib.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 5239230ad075..c826844abdeb 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -674,6 +674,8 @@ irqreturn_t lineevent_irq_thread(int irq, void *p) } else if (le->eflags & GPIOEVENT_REQUEST_FALLING_EDGE) { /* Emit high-to-low event */ ge.id = GPIOEVENT_EVENT_FALLING_EDGE; + } else { + return IRQ_NONE; } ret = kfifo_put(&le->events, ge);