usbcore: cdev lock_kernel() pushdown
usb_open() is protected by a down_read(&minor_rwsem), but I'm not sure I
trust it to protect everything including subsidiary open() functions.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/drivers/usb/core/file.c b/drivers/usb/core/file.c
index 8133c99..c6a9539 100644
--- a/drivers/usb/core/file.c
+++ b/drivers/usb/core/file.c
@@ -18,6 +18,7 @@
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/rwsem.h>
+#include <linux/smp_lock.h>
#include <linux/usb.h>
#include "usb.h"
@@ -33,6 +34,7 @@
int err = -ENODEV;
const struct file_operations *old_fops, *new_fops = NULL;
+ lock_kernel();
down_read(&minor_rwsem);
c = usb_minors[minor];
@@ -51,6 +53,7 @@
fops_put(old_fops);
done:
up_read(&minor_rwsem);
+ unlock_kernel();
return err;
}