From patchwork Mon Feb 20 10:18:57 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Reshetova, Elena" X-Patchwork-Id: 9582393 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id A73AB60578 for ; Mon, 20 Feb 2017 10:24:49 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9744528840 for ; Mon, 20 Feb 2017 10:24:49 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8BB8428851; Mon, 20 Feb 2017 10:24:49 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3BF7528840 for ; Mon, 20 Feb 2017 10:24:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752772AbdBTKYr (ORCPT ); Mon, 20 Feb 2017 05:24:47 -0500 Received: from mga14.intel.com ([192.55.52.115]:49569 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752015AbdBTKYo (ORCPT ); Mon, 20 Feb 2017 05:24:44 -0500 Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Feb 2017 02:24:38 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,186,1484035200"; d="scan'208";a="935966628" Received: from elena-thinkpad-x230.fi.intel.com ([10.237.72.69]) by orsmga003.jf.intel.com with ESMTP; 20 Feb 2017 02:24:32 -0800 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, paul@paul-moore.com, eparis@redhat.com, akpm@linux-foundation.org, arnd@arndb.de, luto@kernel.org, Elena Reshetova , Hans Liljestrand , Kees Cook , David Windsor Subject: [PATCH 08/19] kernel: convert ring_buffer.aux_refcount from atomic_t to refcount_t Date: Mon, 20 Feb 2017 12:18:57 +0200 Message-Id: <1487585948-6401-9-git-send-email-elena.reshetova@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1487585948-6401-1-git-send-email-elena.reshetova@intel.com> References: <1487585948-6401-1-git-send-email-elena.reshetova@intel.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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/events/core.c | 2 +- kernel/events/internal.h | 2 +- kernel/events/ring_buffer.c | 6 +++--- 3 files changed, 5 insertions(+), 5 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index e1c337d..32add6c 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5114,7 +5114,7 @@ static void perf_mmap_close(struct vm_area_struct *vma) /* this has to be the last one */ rb_free_aux(rb); - WARN_ON_ONCE(atomic_read(&rb->aux_refcount)); + WARN_ON_ONCE(refcount_read(&rb->aux_refcount)); mutex_unlock(&event->mmap_mutex); } diff --git a/kernel/events/internal.h b/kernel/events/internal.h index b8e6fdf..fb55716 100644 --- a/kernel/events/internal.h +++ b/kernel/events/internal.h @@ -48,7 +48,7 @@ struct ring_buffer { atomic_t aux_mmap_count; unsigned long aux_mmap_locked; void (*free_aux)(void *); - atomic_t aux_refcount; + refcount_t aux_refcount; void **aux_pages; void *aux_priv; diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c index 8de1664..c501d4e 100644 --- a/kernel/events/ring_buffer.c +++ b/kernel/events/ring_buffer.c @@ -344,7 +344,7 @@ void *perf_aux_output_begin(struct perf_output_handle *handle, if (!atomic_read(&rb->aux_mmap_count)) goto err; - if (!atomic_inc_not_zero(&rb->aux_refcount)) + if (!refcount_inc_not_zero(&rb->aux_refcount)) goto err; /* @@ -636,7 +636,7 @@ int rb_alloc_aux(struct ring_buffer *rb, struct perf_event *event, * we keep a refcount here to make sure either of the two can * reference them safely. */ - atomic_set(&rb->aux_refcount, 1); + refcount_set(&rb->aux_refcount, 1); rb->aux_overwrite = overwrite; rb->aux_watermark = watermark; @@ -655,7 +655,7 @@ int rb_alloc_aux(struct ring_buffer *rb, struct perf_event *event, void rb_free_aux(struct ring_buffer *rb) { - if (atomic_dec_and_test(&rb->aux_refcount)) + if (refcount_dec_and_test(&rb->aux_refcount)) __rb_free_aux(rb); }