Re: Question for Patch"libsas: fix "sysfs group not found" warnings at port teardown time"

[wangyijing <wangyijing@huawei.com>]

在 2016/2/6 5:33, Praveen Murali 写道:
> Hi Yijing,
>   The fix was deemed inappropriate and I think the explanation provided 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 better 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 on this patch,
do you have the link ?


Thanks!
Yijing.


> 
> Praveen
> 
>> On Feb 5, 2016, at 1:20 AM, wangyijing <wangyijing@huawei.com> wrote:
>>
>> Hi Dan and Praveen,
>>   I found a patch titled "libsas: fix "sysfs group not found" warnings at port teardown time" by google,
>> https://www.mail-archive.com/linux-scsi@vger.kernel.org/msg39187.html
>>
>> 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 about 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 = 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 = NULL;
>>
>> ...
>> 	sas_destruct_devices
>> 		sas_port_delete   //now we actually delete the port device, but we set 	phy->port = 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
>> [<ffff800000089918>] dump_backtrace+0x0/0x124
>> [<ffff800000089a4c>] show_stack+0x10/0x1c
>> [<ffff80000009fcbc>] warn_slowpath_fmt+0x4c/0x58
>> [<ffff8000003cdc04>] device_add+0x28c/0x5b8
>> [<ffff80000040d4ec>] sas_port_add+0x20/0xbc
>> [<ffff80000040f3e8>] sas_porte_bytes_dmaed
>> [<ffff8000000b5504>] 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
> 
> 
> .
> 

--
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