From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752843AbdBTLGo (ORCPT ); Mon, 20 Feb 2017 06:06:44 -0500 Received: from mga02.intel.com ([134.134.136.20]:57934 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751436AbdBTLGk (ORCPT ); Mon, 20 Feb 2017 06:06:40 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,186,1484035200"; d="scan'208";a="826325785" From: Elena Reshetova To: linux-kernel@vger.kernel.org Cc: linux-edac@vger.kernel.org, x86@kernel.org, sparclinux@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, peterz@infradead.org, gregkh@linuxfoundation.org, davem@davemloft.net, tglx@linutronix.de, mingo@redhat.com, tony.luck@intel.com, hpa@zytor.com, Elena Reshetova , Hans Liljestrand , Kees Cook , David Windsor Subject: [PATCH 3/4] sparc: convert mdesc_handle.refcnt from atomic_t to refcount_t Date: Mon, 20 Feb 2017 13:06:20 +0200 Message-Id: <1487588781-15123-4-git-send-email-elena.reshetova@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1487588781-15123-1-git-send-email-elena.reshetova@intel.com> References: <1487588781-15123-1-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 --- arch/sparc/kernel/mdesc.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/arch/sparc/kernel/mdesc.c b/arch/sparc/kernel/mdesc.c index c0765bb..ac3fe0d 100644 --- a/arch/sparc/kernel/mdesc.c +++ b/arch/sparc/kernel/mdesc.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include @@ -70,7 +71,7 @@ struct mdesc_handle { struct list_head list; struct mdesc_mem_ops *mops; void *self_base; - atomic_t refcnt; + refcount_t refcnt; unsigned int handle_size; struct mdesc_hdr mdesc; }; @@ -84,7 +85,7 @@ static void mdesc_handle_init(struct mdesc_handle *hp, memset(hp, 0, handle_size); INIT_LIST_HEAD(&hp->list); hp->self_base = base; - atomic_set(&hp->refcnt, 1); + refcount_set(&hp->refcnt, 1); hp->handle_size = handle_size; } @@ -114,7 +115,7 @@ static void __init mdesc_memblock_free(struct mdesc_handle *hp) unsigned int alloc_size; unsigned long start; - BUG_ON(atomic_read(&hp->refcnt) != 0); + BUG_ON(refcount_read(&hp->refcnt) != 0); BUG_ON(!list_empty(&hp->list)); alloc_size = PAGE_ALIGN(hp->handle_size); @@ -154,7 +155,7 @@ static struct mdesc_handle *mdesc_kmalloc(unsigned int mdesc_size) static void mdesc_kfree(struct mdesc_handle *hp) { - BUG_ON(atomic_read(&hp->refcnt) != 0); + BUG_ON(refcount_read(&hp->refcnt) != 0); BUG_ON(!list_empty(&hp->list)); kfree(hp->self_base); @@ -193,7 +194,7 @@ struct mdesc_handle *mdesc_grab(void) spin_lock_irqsave(&mdesc_lock, flags); hp = cur_mdesc; if (hp) - atomic_inc(&hp->refcnt); + refcount_inc(&hp->refcnt); spin_unlock_irqrestore(&mdesc_lock, flags); return hp; @@ -205,7 +206,7 @@ void mdesc_release(struct mdesc_handle *hp) unsigned long flags; spin_lock_irqsave(&mdesc_lock, flags); - if (atomic_dec_and_test(&hp->refcnt)) { + if (refcount_dec_and_test(&hp->refcnt)) { list_del_init(&hp->list); hp->mops->free(hp); } @@ -344,7 +345,7 @@ void mdesc_update(void) if (status != HV_EOK || real_len > len) { printk(KERN_ERR "MD: mdesc reread fails with %lu\n", status); - atomic_dec(&hp->refcnt); + refcount_dec(&hp->refcnt); mdesc_free(hp); goto out; } @@ -357,7 +358,7 @@ void mdesc_update(void) mdesc_notify_clients(orig_hp, hp); spin_lock_irqsave(&mdesc_lock, flags); - if (atomic_dec_and_test(&orig_hp->refcnt)) + if (refcount_dec_and_test(&orig_hp->refcnt)) mdesc_free(orig_hp); else list_add(&orig_hp->list, &mdesc_zombie_list); -- 2.7.4