Avoid usb reset crashes by making tty_io cdevs truly dynamic
Avoid usb reset crashes by making tty_io cdevs truly dynamic
Signed-off-by: Richard Watts <rrw@kynesim.co.uk>
Reported-by: Duncan Mackintosh <DMackintosh@cbnl.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index c37a215..02785d8 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -3152,9 +3152,12 @@
unsigned int index, unsigned int count)
{
/* init here, since reused cdevs cause crashes */
- cdev_init(&driver->cdevs[index], &tty_fops);
- driver->cdevs[index].owner = driver->owner;
- return cdev_add(&driver->cdevs[index], dev, count);
+ driver->cdevs[index] = cdev_alloc();
+ if (!driver->cdevs[index])
+ return -ENOMEM;
+ cdev_init(driver->cdevs[index], &tty_fops);
+ driver->cdevs[index]->owner = driver->owner;
+ return cdev_add(driver->cdevs[index], dev, count);
}
/**
@@ -3260,8 +3263,10 @@
error:
put_device(dev);
- if (cdev)
- cdev_del(&driver->cdevs[index]);
+ if (cdev) {
+ cdev_del(driver->cdevs[index]);
+ driver->cdevs[index] = NULL;
+ }
return ERR_PTR(retval);
}
EXPORT_SYMBOL_GPL(tty_register_device_attr);
@@ -3281,8 +3286,10 @@
{
device_destroy(tty_class,
MKDEV(driver->major, driver->minor_start) + index);
- if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC))
- cdev_del(&driver->cdevs[index]);
+ if (!(driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)) {
+ cdev_del(driver->cdevs[index]);
+ driver->cdevs[index] = NULL;
+ }
}
EXPORT_SYMBOL(tty_unregister_device);
@@ -3347,6 +3354,7 @@
kfree(driver->ports);
kfree(driver->ttys);
kfree(driver->termios);
+ kfree(driver->cdevs);
kfree(driver);
return ERR_PTR(err);
}
@@ -3375,7 +3383,7 @@
}
proc_tty_unregister_driver(driver);
if (driver->flags & TTY_DRIVER_DYNAMIC_ALLOC)
- cdev_del(&driver->cdevs[0]);
+ cdev_del(driver->cdevs[0]);
}
kfree(driver->cdevs);
kfree(driver->ports);