From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, wenxiong@linux.vnet.ibm.com, "James Bottomley" Date: Sun, 29 Dec 2013 03:08:44 +0100 Message-ID: Subject: [PATCH 3.2 114/185] [SCSI] enclosure: fix WARN_ON in dual path device removing In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.2.54-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: James Bottomley commit a1470c7bf3a4676e62e4c0fb204e339399eb5c59 upstream. Bug report from: wenxiong@linux.vnet.ibm.com The issue is happened in dual controller configuration. We got the sysfs warnings when rmmod the ipr module. enclosure_unregister() in drivers/msic/enclosure.c, call device_unregister() for each componment deivce, device_unregister() ->device_del()->kobject_del() ->sysfs_remove_dir(). In sysfs_remove_dir(), set kobj->sd = NULL. For each componment device, enclosure_component_release()->enclosure_remove_links()->sysfs_remove_link() in which checking kobj->sd again, it has been set as NULL when doing device_unregister. So we saw all these sysfs WARNING. Tested-by: wenxiong@linux.vnet.ibm.com Signed-off-by: James Bottomley Signed-off-by: Ben Hutchings --- drivers/misc/enclosure.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/drivers/misc/enclosure.c +++ b/drivers/misc/enclosure.c @@ -198,6 +198,13 @@ static void enclosure_remove_links(struc { char name[ENCLOSURE_NAME_SIZE]; + /* + * In odd circumstances, like multipath devices, something else may + * already have removed the links, so check for this condition first. + */ + if (!cdev->dev->kobj.sd) + return; + enclosure_link_name(cdev, name); sysfs_remove_link(&cdev->dev->kobj, name); sysfs_remove_link(&cdev->cdev.kobj, "device");