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| author | Jia-Ju Bai <baijiaju1990@gmail.com> | 2019-12-18 17:44:05 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-01-14 15:27:51 +0100 |
| commit | b74351287d4bd90636c3f48bc188c2f53824c2d4 (patch) | |
| tree | b90124de8b435f7abaaefe76a4c03dfa96b4934f /drivers/uio | |
| parent | fa4e7fc1386078edcfddd8848cb0374f4af74fe7 (diff) | |
| download | linux-b74351287d4bd90636c3f48bc188c2f53824c2d4.tar.bz2 | |
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/uio')
| -rw-r--r-- | drivers/uio/uio_dmem_genirq.c | 6 |
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; } |