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). Praveen > On Feb 5, 2016, at 1:20 AM, wangyijing <wangyijing@xxxxxxxxxx> 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@xxxxxxxxxxxxxxx/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@xxxxxxxxxxxxxxx > 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@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
