Hello Ralf,
This is a patch that fixes spin_lock deadlock in serial ip3106 driver.
The spin_lock_irq(&port->lock,flags) is already called in generic driver
serial_core.c before
port->ops->start_tx().
So the second call of spin_lock_irq(&port->lock, flags) leads to
deadlock. This could be verified in PREEMPT_DESCTOP case when
these options are enabled:
CONFIG_DEBUG_PREEMPT=y
CONFIG_DEBUG_SPINLOCK=y
Vladimir
--- linux-2.6.15/drivers/serial/ip3106_uart.c 2005-12-02 16:37:59.000000000 +0300
+++ linux-2.6.15/drivers/serial/ip3106_uart.c 2005-12-06 20:40:15.000000000 +0300
@@ -149,19 +149,14 @@ static void ip3106_stop_tx(struct uart_p
static void ip3106_start_tx(struct uart_port *port, unsigned int tty_start)
{
struct ip3106_port *sport = (struct ip3106_port *)port;
- unsigned long flags;
u32 ien;
- spin_lock_irqsave(&sport->port.lock, flags);
-
/* Clear all pending TX intr */
serial_out(sport, IP3106_ICLR, IP3106_UART_INT_ALLTX);
/* Enable TX intr */
ien = serial_in(sport, IP3106_IEN);
serial_out(sport, IP3106_IEN, ien | IP3106_UART_INT_ALLTX);
-
- spin_unlock_irqrestore(&sport->port.lock, flags);
}
/*
