Fix panic caused by a race between men_z135_intr() and men_z135_set_termios().
men_z135_intr() and men_z135_set_termios() both hold the struct uart_port::lock spinlock, but men_z135_intr() does a spin_lock_irqsave() and men_z135_set_termios() does a normal spin_lock(), which can lead to a deadlock when an interrupt is called while the lock is being helt by men_z135_set_termios(). This was discovered using a insmod, hardware looppback send/receive, rmmod stress test. Signed-off-by: Johannes Thumshirn <[email protected]> Cc: Andreas Werner <[email protected]> --- drivers/tty/serial/men_z135_uart.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/men_z135_uart.c b/drivers/tty/serial/men_z135_uart.c index 35c5550..d020435 100644 --- a/drivers/tty/serial/men_z135_uart.c +++ b/drivers/tty/serial/men_z135_uart.c @@ -656,6 +656,7 @@ static void men_z135_set_termios(struct uart_port *port, struct ktermios *old) { struct men_z135_port *uart = to_men_z135(port); + unsigned long flags; unsigned int baud; u32 conf_reg; u32 bd_reg; @@ -717,7 +718,7 @@ static void men_z135_set_termios(struct uart_port *port, baud = uart_get_baud_rate(port, termios, old, 0, uart_freq / 16); - spin_lock(&port->lock); + spin_lock_irqsave(&port->lock, flags); if (tty_termios_baud_rate(termios)) tty_termios_encode_baud_rate(termios, baud, baud); @@ -725,7 +726,7 @@ static void men_z135_set_termios(struct uart_port *port, iowrite32(bd_reg, port->membase + MEN_Z135_BAUD_REG); uart_update_timeout(port, termios->c_cflag, baud); - spin_unlock(&port->lock); + spin_unlock_irqrestore(&port->lock, flags); } static const char *men_z135_type(struct uart_port *port) -- 2.4.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
