tty: don't leak cdev in tty_cdev_add()
Commit a3a10ce3429e ("Avoid usb reset crashes by making tty_io cdevs truly
dynamic") which mixes using cdev_alloc() and cdev_init() is problematic.
Subsequent call to cdev_init() after cdev_alloc() sets kobj release method
from cdev_dynamic_release() to cdev_default_release() and thus makes it
impossible to free allocated cdev.
This patch also consolidates error path of cdev_add() as cdev can also leak
here if things went wrong.
Signed-off-by: Leon Yu <chianglungyu@gmail.com>
Fixes: a3a10ce3429e ("Avoid usb reset crashes by making tty_io cdevs truly dynamic")
Acked-by: Richard Watts <rrw@kynesim.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 02785d8..17b0272 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -3151,13 +3151,18 @@
static int tty_cdev_add(struct tty_driver *driver, dev_t dev,
unsigned int index, unsigned int count)
{
+ int err;
+
/* init here, since reused cdevs cause crashes */
driver->cdevs[index] = cdev_alloc();
if (!driver->cdevs[index])
return -ENOMEM;
- cdev_init(driver->cdevs[index], &tty_fops);
+ driver->cdevs[index]->ops = &tty_fops;
driver->cdevs[index]->owner = driver->owner;
- return cdev_add(driver->cdevs[index], dev, count);
+ err = cdev_add(driver->cdevs[index], dev, count);
+ if (err)
+ kobject_put(&driver->cdevs[index]->kobj);
+ return err;
}
/**
