From: Jia-Ju Bai baijiaju1990@gmail.com
[ Upstream commit e36eaf94be8f7bc4e686246eed3cf92d845e2ef8 ]
The driver may sleep while holding a spinlock. The function call path (from bottom to top) in Linux 4.19 is:
drivers/gpio/gpio-grgpio.c, 261: request_irq in grgpio_irq_map drivers/gpio/gpio-grgpio.c, 255: _raw_spin_lock_irqsave in grgpio_irq_map
drivers/gpio/gpio-grgpio.c, 318: free_irq in grgpio_irq_unmap drivers/gpio/gpio-grgpio.c, 299: _raw_spin_lock_irqsave in grgpio_irq_unmap
request_irq() and free_irq() can sleep at runtime.
To fix these bugs, request_irq() and free_irq() are called without holding the spinlock.
These bugs are found by a static analysis tool STCheck written by myself.
Signed-off-by: Jia-Ju Bai baijiaju1990@gmail.com Link: https://lore.kernel.org/r/20191218132605.10594-1-baijiaju1990@gmail.com Signed-off-by: Linus Walleij linus.walleij@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpio/gpio-grgpio.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/gpio/gpio-grgpio.c b/drivers/gpio/gpio-grgpio.c index 7847dd34f86fc..036a78b704270 100644 --- a/drivers/gpio/gpio-grgpio.c +++ b/drivers/gpio/gpio-grgpio.c @@ -259,17 +259,16 @@ static int grgpio_irq_map(struct irq_domain *d, unsigned int irq, lirq->irq = irq; uirq = &priv->uirqs[lirq->index]; if (uirq->refcnt == 0) { + spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags); ret = request_irq(uirq->uirq, grgpio_irq_handler, 0, dev_name(priv->dev), priv); if (ret) { dev_err(priv->dev, "Could not request underlying irq %d\n", uirq->uirq); - - spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags); - return ret; } + spin_lock_irqsave(&priv->gc.bgpio_lock, flags); } uirq->refcnt++;
@@ -315,8 +314,11 @@ static void grgpio_irq_unmap(struct irq_domain *d, unsigned int irq) if (index >= 0) { uirq = &priv->uirqs[lirq->index]; uirq->refcnt--; - if (uirq->refcnt == 0) + if (uirq->refcnt == 0) { + spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags); free_irq(uirq->uirq, priv); + return; + } }
spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags);