From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751485AbdCAJES (ORCPT ); Wed, 1 Mar 2017 04:04:18 -0500 Received: from mga09.intel.com ([134.134.136.24]:33664 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750941AbdCAJEF (ORCPT ); Wed, 1 Mar 2017 04:04:05 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,224,1484035200"; d="scan'208";a="1103499043" From: Elena Reshetova To: linux-kernel@vger.kernel.org Cc: linux-xfs@vger.kernel.org, peterz@infradead.org, gregkh@linuxfoundation.org, darrick.wong@oracle.com, david@fromorbit.com, Elena Reshetova , Hans Liljestrand , Kees Cook , David Windsor Subject: [PATCH 2/5] fs, xfs: convert xfs_efi_log_item.efi_refcount from atomic_t to refcount_t Date: Wed, 1 Mar 2017 10:47:37 +0200 Message-Id: <1488358060-693-3-git-send-email-elena.reshetova@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1488358060-693-1-git-send-email-elena.reshetova@intel.com> References: <1488358060-693-1-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 --- fs/xfs/xfs_extfree_item.c | 4 ++-- fs/xfs/xfs_extfree_item.h | 4 +++- 2 files changed, 5 insertions(+), 3 deletions(-) diff --git a/fs/xfs/xfs_extfree_item.c b/fs/xfs/xfs_extfree_item.c index d7bc149..4e0acf0 100644 --- a/fs/xfs/xfs_extfree_item.c +++ b/fs/xfs/xfs_extfree_item.c @@ -220,7 +220,7 @@ xfs_efi_init( efip->efi_format.efi_nextents = nextents; efip->efi_format.efi_id = (uintptr_t)(void *)efip; atomic_set(&efip->efi_next_extent, 0); - atomic_set(&efip->efi_refcount, 2); + refcount_set(&efip->efi_refcount, 2); return efip; } @@ -290,7 +290,7 @@ void xfs_efi_release( struct xfs_efi_log_item *efip) { - if (atomic_dec_and_test(&efip->efi_refcount)) { + if (refcount_dec_and_test(&efip->efi_refcount)) { xfs_trans_ail_remove(&efip->efi_item, SHUTDOWN_LOG_IO_ERROR); xfs_efi_item_free(efip); } diff --git a/fs/xfs/xfs_extfree_item.h b/fs/xfs/xfs_extfree_item.h index a32c794..e6da63d 100644 --- a/fs/xfs/xfs_extfree_item.h +++ b/fs/xfs/xfs_extfree_item.h @@ -18,6 +18,8 @@ #ifndef __XFS_EXTFREE_ITEM_H__ #define __XFS_EXTFREE_ITEM_H__ +#include + /* kernel only EFI/EFD definitions */ struct xfs_mount; @@ -64,7 +66,7 @@ struct kmem_zone; */ typedef struct xfs_efi_log_item { xfs_log_item_t efi_item; - atomic_t efi_refcount; + refcount_t efi_refcount; atomic_t efi_next_extent; unsigned long efi_flags; /* misc flags */ xfs_efi_log_format_t efi_format; -- 2.7.4