From b7ddc981d7b9e2fbfb33cb7cc47603d6e5d93bc9 Mon Sep 17 00:00:00 2001 From: Elena Reshetova Date: Mon, 6 Mar 2017 16:21:13 +0200 Subject: [PATCH] drivers, usb: convert dev_data.count from atomic_t to refcount_t refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/legacy/inode.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c index a2c9168..db34b4de 100644 --- a/drivers/usb/gadget/legacy/inode.c +++ b/drivers/usb/gadget/legacy/inode.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include @@ -114,7 +115,7 @@ enum ep0_state { struct dev_data { spinlock_t lock; - atomic_t count; + refcount_t count; enum ep0_state state; /* P: lock */ struct usb_gadgetfs_event event [N_EVENT]; unsigned ev_next; @@ -150,12 +151,12 @@ struct dev_data { static inline void get_dev (struct dev_data *data) { - atomic_inc (&data->count); + refcount_inc (&data->count); } static void put_dev (struct dev_data *data) { - if (likely (!atomic_dec_and_test (&data->count))) + if (likely (!refcount_dec_and_test (&data->count))) return; /* needs no more cleanup */ BUG_ON (waitqueue_active (&data->wait)); @@ -170,7 +171,7 @@ static struct dev_data *dev_new (void) if (!dev) return NULL; dev->state = STATE_DEV_DISABLED; - atomic_set (&dev->count, 1); + refcount_set (&dev->count, 1); spin_lock_init (&dev->lock); INIT_LIST_HEAD (&dev->epfiles); init_waitqueue_head (&dev->wait); -- 2.7.4