Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759577AbdLRQGX (ORCPT ); Mon, 18 Dec 2017 11:06:23 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:40268 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935184AbdLRQEm (ORCPT ); Mon, 18 Dec 2017 11:04:42 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Christoph Hellwig , Sagi Grimberg , Hannes Reinecke , Johannes Thumshirn , Sasha Levin Subject: [PATCH 4.9 150/177] nvme: use kref_get_unless_zero in nvme_find_get_ns Date: Mon, 18 Dec 2017 16:49:33 +0100 Message-Id: <20171218152917.760636874@linuxfoundation.org> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20171218152909.823644066@linuxfoundation.org> References: <20171218152909.823644066@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1211 Lines: 37 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Christoph Hellwig [ Upstream commit 2dd4122854f697afc777582d18548dded03ce5dd ] For kref_get_unless_zero to protect against lookup vs free races we need to use it in all places where we aren't guaranteed to already hold a reference. There is no such guarantee in nvme_find_get_ns, so switch to kref_get_unless_zero in this function. Signed-off-by: Christoph Hellwig Reviewed-by: Sagi Grimberg Reviewed-by: Hannes Reinecke Reviewed-by: Johannes Thumshirn Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/nvme/host/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -1619,7 +1619,8 @@ static struct nvme_ns *nvme_find_get_ns( mutex_lock(&ctrl->namespaces_mutex); list_for_each_entry(ns, &ctrl->namespaces, list) { if (ns->ns_id == nsid) { - kref_get(&ns->kref); + if (!kref_get_unless_zero(&ns->kref)) + continue; ret = ns; break; }