From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Reinecke Subject: Re: [for 4.1 PATCH resend] libsas: fix "sysfs group not found" warnings at port teardown time Date: Sun, 21 Jun 2015 16:27:02 +0200 Message-ID: <5586C9B6.1020706@suse.de> References: <20150618032204.29990.87007.stgit@dwillia2-desk3.amr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20150618032204.29990.87007.stgit@dwillia2-desk3.amr.corp.intel.com> Sender: stable-owner@vger.kernel.org To: Dan Williams , JBottomley@odin.com, hch@lst.de Cc: Praveen Murali , linux-scsi@vger.kernel.org, stable@vger.kernel.org List-Id: linux-scsi@vger.kernel.org On 06/18/2015 05:22 AM, Dan Williams wrote: > Praveen reports: >=20 > After some debugging this is what I have found >=20 > sas_phye_loss_of_signal gets triggered on phy_event from mvsas > sas_phye_loss_of_signal calls sas_deform_port > sas_deform_port posts a DISCE_DESTRUCT event (sas_unregi= ster_domain_devices-> sas_unregister_dev) > sas_deform_port calls sas_port_delete > sas_port_delete calls sas_port_delete_link > sysfs_remove_group: kobject 'port-X:Y' > sas_port_delete calls device_del > sysfs_remove_group: kobject 'port-X:Y' >=20 > sas_destruct_devices gets triggered for the destruct event (DISCE= _DESTRUCT) > sas_destruct_devices calls sas_rphy_delete > sas_rphy_delete calls scsi_remove_device > scsi_remove_device calls __scsi_remove_device > __scsi_remove_device calls bsg_unregister_qu= eue > bsg_unregister_queue -> device_unreg= ister -> device_del -> sysfs_remove_group: kobject 'X:0:0:0' >=20 > Since X:0:0:0 falls under port-X:Y (which got deleted during > sas_port_delete), this call results in the warning. All the later > warnings in the dmesg output I sent earlier are trying to delete = objects > under port-X:Y. Since port-X:Y got recursively deleted, all these= calls > result in warnings. Since, the PHY and DISC events are processed = in two > different work queues (and one triggers the other), is there any = way > other than checking if the object exists in sysfs (in device_del)= before > deleting? >=20 > WARNING: CPU: 2 PID: 6 at fs/sysfs/group.c:219 device_del+0x40/0x= 1c0() > sysfs group ffffffff818b97e0 not found for kobject '2:0:4:0' > [..] > CPU: 2 PID: 6 Comm: kworker/u8:0 Tainted: P W O 3.16.7-c= kt9-logicube-ng.3 #1 > Hardware name: To be filled by O.E.M. To be filled by O.E.M./VT60= 85, BIOS 4.6.5 01/23/2015 > Workqueue: scsi_wq_2 sas_destruct_devices [libsas] > 0000000000000009 ffffffff8151cd18 ffff88011b35bcd8 ffffffff81068= 7b7 > ffff88011a661400 ffff88011b35bd28 ffff8800c6e5e968 ffff880000028= 810 > ffff8800c89f2c00 ffffffff8106881c ffffffff81733b68 0000000000000= 028 > Call Trace: > [] ? dump_stack+0x41/0x51 > [] ? warn_slowpath_common+0x77/0x90 > [] ? warn_slowpath_fmt+0x4c/0x50 > [] ? device_del+0x40/0x1c0 > [] ? device_unregister+0x1a/0x70 > [] ? bsg_unregister_queue+0x5e/0xb0 > [] ? __scsi_remove_device+0xa9/0xd0 [scsi_mod] >=20 > It appears we've always been double deleting the devices below sas_po= rt, > but recent sysfs changes now exposes this problem. Libsas should del= ete > all the devices from rphy down before deleting the parent port. >=20 > Cc: > Reported-by: Praveen Murali > Tested-by: Praveen Murali > Signed-off-by: Dan Williams Reviewed-by: Hannes Reinecke Cheers, Hannes --=20 Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=C3=BCrnberg GF: J. Hawn, J. Guild, F. Imend=C3=B6rffer, HRB 16746 (AG N=C3=BCrnberg= )