Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932400AbbBSNxd (ORCPT ); Thu, 19 Feb 2015 08:53:33 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:39390 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932347AbbBSNx3 (ORCPT ); Thu, 19 Feb 2015 08:53:29 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: "Michael S. Tsirkin" , Luis Henriques Subject: [PATCH 3.16.y-ckt 58/58] virtio_pci: document why we defer kfree Date: Thu, 19 Feb 2015 13:52:28 +0000 Message-Id: <1424353948-31863-59-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1424353948-31863-1-git-send-email-luis.henriques@canonical.com> References: <1424353948-31863-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1507 Lines: 44 3.16.7-ckt7 -stable review patch. If anyone has any objections, please let me know. ------------------ From: "Michael S. Tsirkin" commit a1eb03f546d651a8f39c7d0692b1f7f5b4e7e3cd upstream. The reason we defer kfree until release function is because it's a general rule for kobjects: kfree of the reference counter itself is only legal in the release function. Previous patch didn't make this clear, document this in code. Signed-off-by: Michael S. Tsirkin [ luis: backported to 3.16: - file rename: virtio_pci_legacy.c -> virtio_pci.c ] Signed-off-by: Luis Henriques --- drivers/virtio/virtio_pci.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c index a46570005a98..52c4607fec9e 100644 --- a/drivers/virtio/virtio_pci.c +++ b/drivers/virtio/virtio_pci.c @@ -671,6 +671,9 @@ static void virtio_pci_release_dev(struct device *_d) struct virtio_device *vdev = dev_to_virtio(_d); struct virtio_pci_device *vp_dev = to_vp_device(vdev); + /* As struct device is a kobject, it's not safe to + * free the memory (including the reference counter itself) + * until it's release callback. */ kfree(vp_dev); } -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/