From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932410AbdCFOfU (ORCPT ); Mon, 6 Mar 2017 09:35:20 -0500 Received: from mga07.intel.com ([134.134.136.100]:29441 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751248AbdCFOY4 (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="72745972" 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 07/29] drivers, md: convert dm_dev_internal.count from atomic_t to refcount_t Date: Mon, 6 Mar 2017 16:20:54 +0200 Message-Id: <1488810076-3754-8-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 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/md/dm-table.c | 6 +++--- drivers/md/dm.h | 3 ++- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 3ad16d9..d2e2741 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -416,15 +416,15 @@ int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode, return r; } - atomic_set(&dd->count, 0); + refcount_set(&dd->count, 1); list_add(&dd->list, &t->devices); } else if (dd->dm_dev->mode != (mode | dd->dm_dev->mode)) { r = upgrade_mode(dd, mode, t->md); if (r) return r; + refcount_inc(&dd->count); } - atomic_inc(&dd->count); *result = dd->dm_dev; return 0; @@ -478,7 +478,7 @@ void dm_put_device(struct dm_target *ti, struct dm_dev *d) dm_device_name(ti->table->md), d->name); return; } - if (atomic_dec_and_test(&dd->count)) { + if (refcount_dec_and_test(&dd->count)) { dm_put_table_device(ti->table->md, d); list_del(&dd->list); kfree(dd); diff --git a/drivers/md/dm.h b/drivers/md/dm.h index f298b01..63b8142 100644 --- a/drivers/md/dm.h +++ b/drivers/md/dm.h @@ -19,6 +19,7 @@ #include #include #include +#include #include "dm-stats.h" @@ -38,7 +39,7 @@ */ struct dm_dev_internal { struct list_head list; - atomic_t count; + refcount_t count; struct dm_dev *dm_dev; }; -- 2.7.4