Dear colleagus,
grgpio_irq_unmap() code looks quite suspicious regarding usage of
priv->bgc.lock spinlock.
It locks the spinlock in line 310:
spin_lock_irqsave(&priv->bgc.lock, flags);
and then it can call grgpio_set_imask() in line 317:
grgpio_set_imask(priv, i, 0);
But grgpio_set_imask() unconditionally locks the spinlock by itself.
static void grgpio_set_imask(struct grgpio_priv *priv, unsigned int offset,
int val)
{
struct bgpio_chip *bgc = &priv->bgc;
unsigned long mask = bgc->pin2mask(bgc, offset);
unsigned long flags;
spin_lock_irqsave(&bgc->lock, flags);
if (val)
priv->imask |= mask;
else
priv->imask &= ~mask;
bgc->write_reg(priv->regs + GRGPIO_IMASK, priv->imask);
spin_unlock_irqrestore(&bgc->lock, flags);
}
So, it looks like unavoidable deadlock here.
Found by Linux Driver Verification project (linuxtesting.org).
--
Alexey Khoroshilov
Linux Verification Center, ISPRAS
web: http://linuxtesting.org
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