diff options
| author | Jia-Ju Bai <baijiaju1990@gmail.com> | 2019-12-18 21:26:05 +0800 |
|---|---|---|
| committer | Linus Walleij <linus.walleij@linaro.org> | 2020-01-07 13:37:11 +0100 |
| commit | e36eaf94be8f7bc4e686246eed3cf92d845e2ef8 (patch) | |
| tree | 35e276dbcb0a9666d6e339cbd75e68d4b4f9794d /drivers/gpio | |
| parent | 25d071b3f6dbe4c4b9c9d0df76fbe9292310e799 (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')
| -rw-r--r-- | drivers/gpio/gpio-grgpio.c | 10 |
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); |