Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752936AbdGGJHx (ORCPT ); Fri, 7 Jul 2017 05:07:53 -0400 Received: from mga07.intel.com ([134.134.136.100]:22083 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752478AbdGGJHu (ORCPT ); Fri, 7 Jul 2017 05:07:50 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.40,321,1496127600"; d="scan'208";a="284089061" From: Elena Reshetova To: linux-kernel@vger.kernel.org Cc: cgroups@vger.kernel.org, linux-audit@redhat.com, linux-fsdevel@vger.kernel.org, peterz@infradead.org, gregkh@linuxfoundation.org, viro@zeniv.linux.org.uk, tj@kernel.org, mingo@redhat.com, hannes@cmpxchg.org, lizefan@huawei.com, acme@kernel.org, alexander.shishkin@linux.intel.com, eparis@redhat.com, akpm@linux-foundation.org, arnd@arndb.de, luto@kernel.org, keescook@chromium.org, Elena Reshetova , Hans Liljestrand , David Windsor Subject: [PATCH 15/15] kernel: convert kcov.refcount from atomic_t to refcount_t Date: Fri, 7 Jul 2017 12:04:29 +0300 Message-Id: <1499418269-3686-16-git-send-email-elena.reshetova@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1499418269-3686-1-git-send-email-elena.reshetova@intel.com> References: <1499418269-3686-1-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: 1769 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 --- kernel/kcov.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/kernel/kcov.c b/kernel/kcov.c index cd77199..a6c7df3 100644 --- a/kernel/kcov.c +++ b/kernel/kcov.c @@ -19,6 +19,7 @@ #include #include #include +#include #include /* @@ -35,7 +36,7 @@ struct kcov { * - opened file descriptor * - task with enabled coverage (we can't unwire it from another task) */ - atomic_t refcount; + refcount_t refcount; /* The lock protects mode, size, area and t. */ spinlock_t lock; enum kcov_mode mode; @@ -94,12 +95,12 @@ EXPORT_SYMBOL(__sanitizer_cov_trace_pc); static void kcov_get(struct kcov *kcov) { - atomic_inc(&kcov->refcount); + refcount_inc(&kcov->refcount); } static void kcov_put(struct kcov *kcov) { - if (atomic_dec_and_test(&kcov->refcount)) { + if (refcount_dec_and_test(&kcov->refcount)) { vfree(kcov->area); kfree(kcov); } @@ -175,7 +176,7 @@ static int kcov_open(struct inode *inode, struct file *filep) kcov = kzalloc(sizeof(*kcov), GFP_KERNEL); if (!kcov) return -ENOMEM; - atomic_set(&kcov->refcount, 1); + refcount_set(&kcov->refcount, 1); spin_lock_init(&kcov->lock); filep->private_data = kcov; return nonseekable_open(inode, filep); -- 2.7.4