uio: fix a sleep-in-atomic-context bug in uio_dmem_genirq_irqcontrol()
[ Upstream commit b74351287d
]
The driver may sleep while holding a spinlock.
The function call path (from bottom to top) in Linux 4.19 is:
kernel/irq/manage.c, 523:
synchronize_irq in disable_irq
drivers/uio/uio_dmem_genirq.c, 140:
disable_irq in uio_dmem_genirq_irqcontrol
drivers/uio/uio_dmem_genirq.c, 134:
_raw_spin_lock_irqsave in uio_dmem_genirq_irqcontrol
synchronize_irq() can sleep at runtime.
To fix this bug, disable_irq() is called without holding the spinlock.
This bug is 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/20191218094405.6009-1-baijiaju1990@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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parent
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@ -132,11 +132,13 @@ static int uio_dmem_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
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if (irq_on) {
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if (test_and_clear_bit(0, &priv->flags))
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enable_irq(dev_info->irq);
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spin_unlock_irqrestore(&priv->lock, flags);
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} else {
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if (!test_and_set_bit(0, &priv->flags))
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if (!test_and_set_bit(0, &priv->flags)) {
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spin_unlock_irqrestore(&priv->lock, flags);
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disable_irq(dev_info->irq);
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}
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}
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spin_unlock_irqrestore(&priv->lock, flags);
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return 0;
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}
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