Messages in this thread Patch in this message | | | From | Leon Yu <> | Subject | [PATCH] tty: don't leak cdev in tty_cdev_add() | Date | Mon, 7 Sep 2015 13:08:37 +0000 |
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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") --- drivers/tty/tty_io.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
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 @@ struct class *tty_class; 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; } /** -- 2.5.1
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