Re: [PATCH 1/1] s390/dasd: Fix inconsistent kobject removal

On Mon, 18 Jan 2021 17:55:18 +0100
Stefan Haberland [off-list ref] wrote:

From: Jan Höppner <hoeppner@linux.ibm.com>

Our intention was to only remove path kobjects whenever a device is
being set offline. However, one corner case was missing.

If a device is disabled and enabled (using the IOCTLs BIODASDDISABLE and
BIODASDENABLE respectively), the enabling process will call
dasd_eckd_reload_device() which itself calls dasd_eckd_read_conf() in
order to update path information. During that update,
dasd_eckd_clear_conf_data() clears all old data and also removes all
kobjects. This will leave us with an inconsistent state of path kobjects
and a subsequent path verification leads to a failing kobject creation.

Fix this by removing kobjects only in the context of offlining a device
as initially intended.

Fixes: 19508b204740 ("s390/dasd: Display FC Endpoint Security information via sysfs")
Reported-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
---
 drivers/s390/block/dasd_devmap.c | 20 ++++++++++++++------
 drivers/s390/block/dasd_eckd.c   |  3 ++-
 drivers/s390/block/dasd_int.h    |  2 +-
 3 files changed, 17 insertions(+), 8 deletions(-)

Reviewed-by: Cornelia Huck <cohuck@redhat.com>