From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758249AbcC3Aqs (ORCPT ); Tue, 29 Mar 2016 20:46:48 -0400 Received: from mail-pf0-f194.google.com ([209.85.192.194]:35378 "EHLO mail-pf0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751128AbcC3Aqq (ORCPT ); Tue, 29 Mar 2016 20:46:46 -0400 From: Ming Lei To: Jens Axboe , linux-kernel@vger.kernel.org Cc: linux-block@vger.kernel.org, Christoph Hellwig , Naveen Kaje , Ming Lei , Subject: [PATCH] block: partition: initialize percpuref before sending out KOBJ_ADD Date: Wed, 30 Mar 2016 08:46:31 +0800 Message-Id: <1459298791-32447-1-git-send-email-ming.lei@canonical.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The initialization of partition's percpu_ref should have been done before sending out KOBJ_ADD uevent, which may cause userspace to read partition table. So the uninitialized percpu_ref may be accessed in data path. This patch fixes this issue reported by Naveen. Reported-by: Naveen Kaje Tested-by: Naveen Kaje Fixes: 6c71013ecb7e2(block: partition: convert percpu ref) Cc: # v4.3+ Signed-off-by: Ming Lei --- block/partition-generic.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/block/partition-generic.c b/block/partition-generic.c index 5d87019..84c53f0 100644 --- a/block/partition-generic.c +++ b/block/partition-generic.c @@ -361,15 +361,20 @@ struct hd_struct *add_partition(struct gendisk *disk, int partno, goto out_del; } + err = hd_ref_init(p); + if (err) { + if (flags & ADDPART_FLAG_WHOLEDISK) + goto out_remove_file; + goto out_del; + } + /* everything is up and running, commence */ rcu_assign_pointer(ptbl->part[partno], p); /* suppress uevent if the disk suppresses it */ if (!dev_get_uevent_suppress(ddev)) kobject_uevent(&pdev->kobj, KOBJ_ADD); - - if (!hd_ref_init(p)) - return p; + return p; out_free_info: free_part_info(p); @@ -378,6 +383,8 @@ out_free_stats: out_free: kfree(p); return ERR_PTR(err); +out_remove_file: + device_remove_file(pdev, &dev_attr_whole_disk); out_del: kobject_put(p->holder_dir); device_del(pdev); -- 1.9.1