serial: core: fix -EPROBE_DEFER handling in init

The -EPROBE_DEFER error path in serial_base_device_init() is a bit
awkward.  Before the call to device_initialize(dev) then we need to
manually release all the device resources.  And after the call then we
need to call put_device() to release the resources.  Doing either one
wrong will result in a leak or a use after free.

So let's wait to return -EPROBE_DEFER until after the call to
device_initialize(dev) so that way callers do not have to handle
-EPROBE_DEFER as a special case.  Now callers can just use put_device()
for clean up.

The second issue with the -EPROBE_DEFER path is that deferring is not
supposed to be a fatal error, but instead it's normal part of the
init process and the kernel recovers from it automatically.  That means
we should not print an error message but just a debug message on this
path.

Fixes: 539914240a01 ("serial: core: Fix probing serial_base_bus devices")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Message-ID: <18318adb-ab2c-4dcc-9f96-498a13d16b80@moroto.mountain>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/serial_base_bus.c b/drivers/tty/serial/serial_base_bus.c
index 9de9f6fa6481fe2f15d3e62ed0ec251fe44228fc..6ff59c89d867d0cb73f7a00ad2729dc98cbd7621 100644 (file)
--- a/drivers/tty/serial/serial_base_bus.c
+++ b/drivers/tty/serial/serial_base_bus.c
@@ -50,17 +50,17 @@ static int serial_base_device_init(struct uart_port *port,
                                   void (*release)(struct device *dev),
                                   int id)
 {
-       if (!serial_base_initialized) {
-               dev_err(port->dev, "uart_add_one_port() called before arch_initcall()?\n");
-               return -EPROBE_DEFER;
-       }
-
        device_initialize(dev);
        dev->type = type;
        dev->parent = parent_dev;
        dev->bus = &serial_base_bus_type;
        dev->release = release;
 
+       if (!serial_base_initialized) {
+               dev_dbg(port->dev, "uart_add_one_port() called before arch_initcall()?\n");
+               return -EPROBE_DEFER;
+       }
+
        return dev_set_name(dev, "%s.%s.%d", type->name, dev_name(port->dev), id);
 }