diff options
| author | Jia-Ju Bai <baijiaju1990@gmail.com> | 2019-12-18 17:44:05 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-02-28 15:42:20 +0100 |
| commit | b77fa964ecb1d72a671234f5bea95b41f77c233a (patch) | |
| tree | baf1b448a9a24ddaf4f95b26555a1cfa3735e223 /drivers/uio | |
| parent | f1af15f459b34c0bd39b19afc1ed9855891da771 (diff) | |
uio: fix a sleep-in-atomic-context bug in uio_dmem_genirq_irqcontrol()
[ 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>
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 e1134a4d97f3..a00b4aee6c79 100644 --- a/drivers/uio/uio_dmem_genirq.c +++ b/drivers/uio/uio_dmem_genirq.c @@ -135,11 +135,13 @@ 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; } |