Avoid usb reset crashes by making tty_io cdevs truly dynamic
Signed-off-by: Richard Watts <[email protected]>
Reported-by: Duncan Mackintosh <[email protected]>
---
drivers/tty/tty_io.c | 24 ++++++++++++++++--------
include/linux/tty_driver.h | 2 +-
2 files changed, 17 insertions(+), 9 deletions(-)
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index e569546..699cf20 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -3168,9 +3168,12 @@ static int tty_cdev_add(struct tty_driver
*driver, dev_t dev,
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);
}
/**
@@ -3276,8 +3279,10 @@ struct device *tty_register_device_attr(struct
tty_driver *driver,
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);
@@ -3297,8 +3302,10 @@ void tty_unregister_device(struct tty_driver
*driver, unsigned index)
{
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);
@@ -3363,6 +3370,7 @@ err_free_all:
kfree(driver->ports);
kfree(driver->ttys);
kfree(driver->termios);
+ kfree(driver->cdevs);
kfree(driver);
return ERR_PTR(err);
}
@@ -3391,7 +3399,7 @@ static void destruct_tty_driver(struct kref *kref)
}
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);
diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
index 92e337c..1610524 100644
--- a/include/linux/tty_driver.h
+++ b/include/linux/tty_driver.h
@@ -296,7 +296,7 @@ struct tty_operations {
struct tty_driver {
int magic; /* magic number for this structure */
struct kref kref; /* Reference management */
- struct cdev *cdevs;
+ struct cdev **cdevs;
struct module *owner;
const char *driver_name;
const char *name;
--
1.9.1
--
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