Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932498AbdCFOgR (ORCPT ); Mon, 6 Mar 2017 09:36:17 -0500 Received: from mga14.intel.com ([192.55.52.115]:31965 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754732AbdCFOgD (ORCPT ); Mon, 6 Mar 2017 09:36:03 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,254,1484035200"; d="scan'208";a="72746236" 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 15/29] drivers, media: convert vb2_dma_sg_buf.refcount from atomic_t to refcount_t Date: Mon, 6 Mar 2017 16:21:02 +0200 Message-Id: <1488810076-3754-16-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: 2412 Lines: 73 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/media/v4l2-core/videobuf2-dma-sg.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/media/v4l2-core/videobuf2-dma-sg.c b/drivers/media/v4l2-core/videobuf2-dma-sg.c index ecff8f4..29fde1a 100644 --- a/drivers/media/v4l2-core/videobuf2-dma-sg.c +++ b/drivers/media/v4l2-core/videobuf2-dma-sg.c @@ -12,6 +12,7 @@ #include #include +#include #include #include #include @@ -46,7 +47,7 @@ struct vb2_dma_sg_buf { struct sg_table *dma_sgt; size_t size; unsigned int num_pages; - atomic_t refcount; + refcount_t refcount; struct vb2_vmarea_handler handler; struct dma_buf_attachment *db_attach; @@ -150,7 +151,7 @@ static void *vb2_dma_sg_alloc(struct device *dev, unsigned long dma_attrs, buf->handler.put = vb2_dma_sg_put; buf->handler.arg = buf; - atomic_inc(&buf->refcount); + refcount_set(&buf->refcount, 1); dprintk(1, "%s: Allocated buffer of %d pages\n", __func__, buf->num_pages); @@ -176,7 +177,7 @@ static void vb2_dma_sg_put(void *buf_priv) struct sg_table *sgt = &buf->sg_table; int i = buf->num_pages; - if (atomic_dec_and_test(&buf->refcount)) { + if (refcount_dec_and_test(&buf->refcount)) { dprintk(1, "%s: Freeing buffer of %d pages\n", __func__, buf->num_pages); dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, @@ -320,7 +321,7 @@ static unsigned int vb2_dma_sg_num_users(void *buf_priv) { struct vb2_dma_sg_buf *buf = buf_priv; - return atomic_read(&buf->refcount); + return refcount_read(&buf->refcount); } static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma) @@ -530,7 +531,7 @@ static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags return NULL; /* dmabuf keeps reference to vb2 buffer */ - atomic_inc(&buf->refcount); + refcount_inc(&buf->refcount); return dbuf; } -- 2.7.4