korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-11 04:18:39 +08:00
Code Issues Packages Projects Releases Wiki Activity

serial: Clear UPF_DEAD before calling tty_port_register_device_attr_serdev()

Browse Source 
If a serdev_device_driver is already loaded for a serdev_tty_port when it
gets registered by tty_port_register_device_attr_serdev() then that
driver's probe() method will be called immediately.

The serdev_device_driver's probe() method should then be able to call
serdev_device_open() successfully, but because UPF_DEAD is still dead
serdev_device_open() will fail with -ENXIO in this scenario:

  serdev_device_open()
  ctrl->ops->open()	/* this callback being ttyport_open() */
  tty->ops->open()	/* this callback being uart_open() */
  tty_port_open()
  port->ops->activate()	/* this callback being uart_port_activate() */
  Find bit UPF_DEAD is set in uport->flags and fail with errno -ENXIO.

Fix this be clearing UPF_DEAD before tty_port_register_device_attr_serdev()
note this only moves up the UPD_DEAD clearing a small bit, before:

  tty_port_register_device_attr_serdev();
  mutex_unlock(&tty_port.mutex);
  uart_port.flags &= ~UPF_DEAD;
  mutex_unlock(&port_mutex);

after:

  uart_port.flags &= ~UPF_DEAD;
  tty_port_register_device_attr_serdev();
  mutex_unlock(&tty_port.mutex);
  mutex_unlock(&port_mutex);

Reported-by: Weifeng Liu <weifeng.liu.z@gmail.com>
Closes: https://lore.kernel.org/platform-driver-x86/20240505130800.2546640-1-weifeng.liu.z@gmail.com/
Tested-by: Weifeng Liu <weifeng.liu.z@gmail.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20240509141549.63704-1-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Hans de Goede 2024-05-09 16:15:49 +02:00 committed by Greg Kroah-Hartman
parent a3d8728ab0
commit e21de1455a
1 changed files with 4 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/tty/serial/serial_core.c
View File

@ -3207,6 +3207,9 @@ static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *u
if (uport->attr_group)
uport->tty_groups[1] = uport->attr_group;
/* Ensure serdev drivers can call serdev_device_open() right away */
uport->flags &= ~UPF_DEAD;
/*
* Register the port whether it's detected or not. This allows
* setserial to be used to alter this port's parameters.
@ -3217,6 +3220,7 @@ static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *u
if (!IS_ERR(tty_dev)) {
device_set_wakeup_capable(tty_dev, 1);
} else {
uport->flags |= UPF_DEAD;
dev_err(uport->dev, "Cannot register tty device on line %d\n",
uport->line);
}
@ -3426,8 +3430,6 @@ int serial_core_register_port(struct uart_driver *drv, struct uart_port *port)
if (ret)
goto err_unregister_port_dev;
port->flags &= ~UPF_DEAD;
mutex_unlock(&port_mutex);
return 0;