diff options
author | Jia-Ju Bai <baijiaju1990@gmail.com> | 2019-12-18 16:26:05 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-02-28 17:42:18 +0300 |
commit | fd0faee0f5bc19ac5226f1c3465dd4200311afc2 (patch) | |
tree | b8126d573b14c835f0cda9a225f8009c37726582 | |
parent | b25c67a31420abd86ccbc1ecdaad898e7f8b135b (diff) | |
download | linux-fd0faee0f5bc19ac5226f1c3465dd4200311afc2.tar.xz |
gpio: gpio-grgpio: fix possible sleep-in-atomic-context bugs in grgpio_irq_map/unmap()
[ 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>
-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 7847dd34f86f..036a78b70427 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); |