Messages in this thread Patch in this message | | | From | Elena Reshetova <> | Subject | [PATCH 27/29] drivers, usb: convert ep_data.count from atomic_t to refcount_t | Date | Mon, 6 Mar 2017 16:21:14 +0200 |
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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 <elena.reshetova@intel.com> Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David Windsor <dwindsor@gmail.com> --- drivers/usb/gadget/legacy/inode.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c index 81d76f3..d21a5f8 100644 --- a/drivers/usb/gadget/legacy/inode.c +++ b/drivers/usb/gadget/legacy/inode.c @@ -191,7 +191,7 @@ enum ep_state { struct ep_data { struct mutex lock; enum ep_state state; - atomic_t count; + refcount_t count; struct dev_data *dev; /* must hold dev->lock before accessing ep or req */ struct usb_ep *ep; @@ -206,12 +206,12 @@ struct ep_data { static inline void get_ep (struct ep_data *data) { - atomic_inc (&data->count); + refcount_inc (&data->count); } static void put_ep (struct ep_data *data) { - if (likely (!atomic_dec_and_test (&data->count))) + if (likely (!refcount_dec_and_test (&data->count))) return; put_dev (data->dev); /* needs no more cleanup */ @@ -1562,7 +1562,7 @@ static int activate_ep_files (struct dev_data *dev) init_waitqueue_head (&data->wait); strncpy (data->name, ep->name, sizeof (data->name) - 1); - atomic_set (&data->count, 1); + refcount_set (&data->count, 1); data->dev = dev; get_dev (dev); -- 2.7.4
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