From: Jia-Ju Bai baijiaju1990@gmail.com
[ Upstream commit b74351287d4bd90636c3f48bc188c2f53824c2d4 ]
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 --- drivers/uio/uio_dmem_genirq.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/uio/uio_dmem_genirq.c b/drivers/uio/uio_dmem_genirq.c index 81c88f7bbbcbb..f6ab3f28c8382 100644 --- a/drivers/uio/uio_dmem_genirq.c +++ b/drivers/uio/uio_dmem_genirq.c @@ -132,11 +132,13 @@ static int uio_dmem_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on) if (irq_on) { if (test_and_clear_bit(0, &priv->flags)) enable_irq(dev_info->irq); + spin_unlock_irqrestore(&priv->lock, flags); } else { - if (!test_and_set_bit(0, &priv->flags)) + if (!test_and_set_bit(0, &priv->flags)) { + spin_unlock_irqrestore(&priv->lock, flags); disable_irq(dev_info->irq); + } } - spin_unlock_irqrestore(&priv->lock, flags);
return 0; }