ali_ircc_sir_change_speed() is always called with self->lock held,
so acquiring the lock inside it leads to unavoidable deadlock.
Call graph:
ali_ircc_sir_change_speed() is called from ali_ircc_change_speed()
ali_ircc_fir_hard_xmit() under spin_lock_irqsave(&self->lock, flags);
ali_ircc_sir_hard_xmit() under spin_lock_irqsave(&self->lock, flags);
ali_ircc_net_ioctl() under spin_lock_irqsave(&self->lock, flags);
ali_ircc_dma_xmit_complete()
ali_ircc_fir_interrupt()
ali_ircc_interrupt() under spin_lock(&self->lock);
ali_ircc_sir_write_wakeup()
ali_ircc_sir_interrupt()
ali_ircc_interrupt() under spin_lock(&self->lock);
The patch removes spin_lock/unlock from ali_ircc_sir_change_speed().
Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
static void ali_ircc_sir_change_speed(struct ali_ircc_cb *priv, __u32 speed)
{
struct ali_ircc_cb *self = priv;
static void ali_ircc_sir_change_speed(struct ali_ircc_cb *priv, __u32 speed)
{
struct ali_ircc_cb *self = priv;
int iobase;
int fcr; /* FIFO control reg */
int lcr; /* Line control reg */
int iobase;
int fcr; /* FIFO control reg */
int lcr; /* Line control reg */
/* Update accounting for new speed */
self->io.speed = speed;
/* Update accounting for new speed */
self->io.speed = speed;
- spin_lock_irqsave(&self->lock, flags);
-
divisor = 115200/speed;
fcr = UART_FCR_ENABLE_FIFO;
divisor = 115200/speed;
fcr = UART_FCR_ENABLE_FIFO;
/* without this, the connection will be broken after come back from FIR speed,
but with this, the SIR connection is harder to established */
outb((UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2), iobase+UART_MCR);
/* without this, the connection will be broken after come back from FIR speed,
but with this, the SIR connection is harder to established */
outb((UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2), iobase+UART_MCR);
-
- spin_unlock_irqrestore(&self->lock, flags);
-
}
static void ali_ircc_change_dongle_speed(struct ali_ircc_cb *priv, int speed)
}
static void ali_ircc_change_dongle_speed(struct ali_ircc_cb *priv, int speed)