Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932243AbdCFOZn (ORCPT ); Mon, 6 Mar 2017 09:25:43 -0500 Received: from mga05.intel.com ([192.55.52.43]:47276 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753150AbdCFOY4 (ORCPT ); Mon, 6 Mar 2017 09:24:56 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,254,1484035200"; d="scan'208";a="72746555" From: Elena Reshetova To: gregkh@linuxfoundation.org Cc: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, netdev@vger.kernel.org, linux1394-devel@lists.sourceforge.net, linux-bcache@vger.kernel.org, linux-raid@vger.kernel.org, linux-media@vger.kernel.org, devel@linuxdriverproject.org, linux-pci@vger.kernel.org, linux-s390@vger.kernel.org, fcoe-devel@open-fcoe.org, linux-scsi@vger.kernel.org, open-iscsi@googlegroups.com, devel@driverdev.osuosl.org, target-devel@vger.kernel.org, linux-serial@vger.kernel.org, linux-usb@vger.kernel.org, peterz@infradead.org, Elena Reshetova , Hans Liljestrand , Kees Cook , David Windsor Subject: [PATCH 26/29] drivers, usb: convert dev_data.count from atomic_t to refcount_t Date: Mon, 6 Mar 2017 16:21:13 +0200 Message-Id: <1488810076-3754-27-git-send-email-elena.reshetova@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1488810076-3754-1-git-send-email-elena.reshetova@intel.com> References: <1488810076-3754-1-git-send-email-elena.reshetova@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1845 Lines: 61 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 --- 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 79a2d8f..81d76f3 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