From mboxrd@z Thu Jan 1 00:00:00 1970 From: wangyijing Subject: Re: Question for Patch"libsas: fix "sysfs group not found" warnings at port teardown time" Date: Sat, 6 Feb 2016 09:26:24 +0800 Message-ID: <56B54BC0.4010506@huawei.com> References: <56B46943.5040808@huawei.com> <73C1379F-2511-4C31-AB88-65061EBFAEBC@logicube.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from szxga05-in.huawei.com ([119.145.14.199]:20181 "EHLO szxga05-in.huawei.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1750815AbcBFB04 (ORCPT ); Fri, 5 Feb 2016 20:26:56 -0500 In-Reply-To: <73C1379F-2511-4C31-AB88-65061EBFAEBC@logicube.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Praveen Murali Cc: "dan.j.williams@intel.com" , "linux-scsi@vger.kernel.org" , James Bottomley =E5=9C=A8 2016/2/6 5:33, Praveen Murali =E5=86=99=E9=81=93: > Hi Yijing, > The fix was deemed inappropriate and I think the explanation provid= ed by James was kind similar to what your observation is. Also, as far = as I remember the consensus was that these error messages (sysfs group = not found) are harmless at this point. I think James can provide a bett= er explanation and direction for you (copying him here). Hi Praveen, thanks for your reply. This call trace seems to be harmless= , but it's a bad impression to users. I didn't find the James comment o= n this patch, do you have the link ? Thanks! Yijing. >=20 > Praveen >=20 >> On Feb 5, 2016, at 1:20 AM, wangyijing wrote= : >> >> Hi Dan and Praveen, >> I found a patch titled "libsas: fix "sysfs group not found" warnin= gs at port teardown time" by google, >> https://www.mail-archive.com/linux-scsi@vger.kernel.org/msg39187.htm= l >> >> I found the same warning calltrace in my platform, but I didn't find= the patch changes in the latest kernel 4.5-rc2. >> So is this issue still in kernel ? >> >> I think your patch could fix this issue we found, but I'm worried ab= out another problem. >> >> Now when unplug a disk >> >> LLDD report a event loss_of_singal >> sas_deform_port >> sas_unregister_domain_devices >> sas_unregister_dev >> sas_discover_event(dev->port, DISCE_DESTRUCT); >> sas_port_delete >> phy->port =3D NULL; >> >> and after your patch changes >> >> LLDD report a event loss_of_singal >> sas_deform_port >> sas_unregister_domain_devices >> sas_unregister_dev >> sas_discover_event(dev->port, DISCE_DESTRUCT); >> phy->port =3D NULL; >> >> ... >> sas_destruct_devices >> sas_port_delete //now we actually delete the port device, but we= set phy->port =3D NULL; before this time. >> >> >> So if we hotplug the disk quickly, plug,unplug,plug, >> The new dmaed event(plug) would try to alloc and add a new port, but= the old port device is still alive. >> Another calltrace would occur >> >> WARNING: CPU: 0 PID: 1038 at lib/kobject.c:240 kobject_add_internal+= 0x258/0x318() >> kobject_add_internal failed for port-0:0 with -EEXIST, don't try to = register things with the same name in the same directory. >> CPU: 0 PID: 1038 Comm: kworker/u64:2 Tainted: G W 4.1.6= + #140 >> [] dump_backtrace+0x0/0x124 >> [] show_stack+0x10/0x1c >> [] warn_slowpath_fmt+0x4c/0x58 >> [] device_add+0x28c/0x5b8 >> [] sas_port_add+0x20/0xbc >> [] sas_porte_bytes_dmaed >> [] process_one_work+0x13c/0x344 >> >> Because I am not a sas guy, so if you could comment this or post new= patch, I would be thanks a lot! >> >> Thanks! >> Yijing. >> >> >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-scsi= " in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >=20 >=20 > . >=20 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html