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authorJia-Ju Bai <baijiaju1990@gmail.com>2019-12-18 21:26:05 +0800
committerLinus Walleij <linus.walleij@linaro.org>2020-01-07 13:37:11 +0100
commite36eaf94be8f7bc4e686246eed3cf92d845e2ef8 (patch)
tree35e276dbcb0a9666d6e339cbd75e68d4b4f9794d /drivers/gpio/gpio-grgpio.c
parent25d071b3f6dbe4c4b9c9d0df76fbe9292310e799 (diff)
gpio: gpio-grgpio: fix possible sleep-in-atomic-context bugs in grgpio_irq_map/unmap()
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>
Diffstat (limited to 'drivers/gpio/gpio-grgpio.c')
-rw-r--r--drivers/gpio/gpio-grgpio.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/gpio/gpio-grgpio.c b/drivers/gpio/gpio-grgpio.c
index a49f0711ca94..1922adf96fc9 100644
--- a/drivers/gpio/gpio-grgpio.c
+++ b/drivers/gpio/gpio-grgpio.c
@@ -253,17 +253,16 @@ 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++;
@@ -309,8 +308,11 @@ 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);