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authorJia-Ju Bai <baijiaju1990@gmail.com>2019-12-18 17:44:05 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-01-14 15:27:51 +0100
commitb74351287d4bd90636c3f48bc188c2f53824c2d4 (patch)
treeb90124de8b435f7abaaefe76a4c03dfa96b4934f /drivers
parentfa4e7fc1386078edcfddd8848cb0374f4af74fe7 (diff)
uio: fix a sleep-in-atomic-context bug in uio_dmem_genirq_irqcontrol()
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>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/uio/uio_dmem_genirq.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/uio/uio_dmem_genirq.c b/drivers/uio/uio_dmem_genirq.c
index 81c88f7bbbcb..f6ab3f28c838 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;
}