Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932444AbdCFOfc (ORCPT ); Mon, 6 Mar 2017 09:35:32 -0500 Received: from mga11.intel.com ([192.55.52.93]:42872 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753216AbdCFOY4 (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="72745773" 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 01/29] drivers, block: convert xen_blkif.refcnt from atomic_t to refcount_t Date: Mon, 6 Mar 2017 16:20:48 +0200 Message-Id: <1488810076-3754-2-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: 2180 Lines: 64 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/block/xen-blkback/common.h | 7 ++++--- drivers/block/xen-blkback/xenbus.c | 2 +- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h index dea61f6..2ccfd62 100644 --- a/drivers/block/xen-blkback/common.h +++ b/drivers/block/xen-blkback/common.h @@ -35,6 +35,7 @@ #include #include #include +#include #include #include #include @@ -333,7 +334,7 @@ struct xen_blkif { struct xen_vbd vbd; /* Back pointer to the backend_info. */ struct backend_info *be; - atomic_t refcnt; + refcount_t refcnt; /* for barrier (drain) requests */ struct completion drain_complete; atomic_t drain; @@ -386,10 +387,10 @@ struct pending_req { (_v)->bdev->bd_part->nr_sects : \ get_capacity((_v)->bdev->bd_disk)) -#define xen_blkif_get(_b) (atomic_inc(&(_b)->refcnt)) +#define xen_blkif_get(_b) (refcount_inc(&(_b)->refcnt)) #define xen_blkif_put(_b) \ do { \ - if (atomic_dec_and_test(&(_b)->refcnt)) \ + if (refcount_dec_and_test(&(_b)->refcnt)) \ schedule_work(&(_b)->free_work);\ } while (0) diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c index 8fe61b5..9f89be3 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -176,7 +176,7 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid) return ERR_PTR(-ENOMEM); blkif->domid = domid; - atomic_set(&blkif->refcnt, 1); + refcount_set(&blkif->refcnt, 1); init_completion(&blkif->drain_complete); INIT_WORK(&blkif->free_work, xen_blkif_deferred_free); -- 2.7.4