usbconfig reset ugen4.2 hanging since an hour

Tue Nov 2 10:01:44 UTC 2010

Quoting Hans Petter Selasky <hselasky at freebsd.org> (from Tue, 2 Nov  
2010 10:36:41 +0100):

> On Tuesday 02 November 2010 10:32:08 Alexander Leidinger wrote:
>> Hi,
>>
>> I have a memory stick which made problems (the stick is used as a ZFS
>> cache and it moaned about 8xxM write problems) in 9-current r214509. I
>> removed the device from the config, made a camcontrol reset all,
>> camcontrol rescan all (-> device disappeared), and then tried an
>> usbconfig reset ugen4.2 (relevant devlist part from before the call is
>> below). The usbconfig reset does not return to the shell.
>>
>> I do not know if the problem with the USB memory stick is related to
>> software or hardware. The stick survived just a weekend, I replaced it
>> because the old one showed similar problems after surviving about 9
>> months... I updated -current just before the problems appeared (and
>> then again after a week or two), but I do not remember from which
>> revision of -current I was updating from. I will try to stress-test
>> the memory sticks on a 8.1 system so see if it is some software problem.
>>
>> The big question I have for now is: shouldn't there be some kind of
>> safety mechanism kicking in (timeout) with the usbconfig command (in
>> this case the reset)?
>>
>> devlist:
>> ---snip---
>> ugen4.1: <EHCI root HUB Intel> at usbus4, cfg=0 md=HOST spd=HIGH
>> (480Mbps) pwr=SAVE
>> ugen4.2: <Flash Disk USB 2.0> at usbus4, cfg=0 md=HOST spd=HIGH
>> (480Mbps) pwr=ON
>> ---snip---
>>
>> dmesg | grep -i usb:
>> ---snip---
>> uhci0: <Intel 82801EB (ICH5) USB controller USB-A> port 0xdc00-0xdc1f
>> irq 16 at device 29.0 on pci0
>> usbus0: <Intel 82801EB (ICH5) USB controller USB-A> on uhci0
>> uhci1: <Intel 82801EB (ICH5) USB controller USB-B> port 0xe000-0xe01f
>> irq 19 at device 29.1 on pci0
>> usbus1: <Intel 82801EB (ICH5) USB controller USB-B> on uhci1
>> uhci2: <Intel 82801EB (ICH5) USB controller USB-C> port 0xe400-0xe41f
>> irq 18 at device 29.2 on pci0
>> usbus2: <Intel 82801EB (ICH5) USB controller USB-C> on uhci2
>> uhci3: <Intel 82801EB (ICH5) USB controller USB-D> port 0xe800-0xe81f
>> irq 16 at device 29.3 on pci0
>> usbus3: <Intel 82801EB (ICH5) USB controller USB-D> on uhci3
>> ehci0: <Intel 82801EB/R (ICH5) USB 2.0 controller> mem
>> 0xfe77fc00-0xfe77ffff irq 23 at device 29.7 on pci0
>> usbus4: EHCI version 1.0
>> usbus4: <Intel 82801EB/R (ICH5) USB 2.0 controller> on ehci0
>> usbus0: 12Mbps Full Speed USB v1.0
>> usbus1: 12Mbps Full Speed USB v1.0
>> usbus2: 12Mbps Full Speed USB v1.0
>> usbus3: 12Mbps Full Speed USB v1.0
>> usbus4: 480Mbps High Speed USB v2.0
>> ugen0.1: <Intel> at usbus0
>> uhub0: <Intel UHCI root HUB, class 9/0, rev 1.00/1.00, addr 1> on usbus0
>> ugen1.1: <Intel> at usbus1
>> uhub1: <Intel UHCI root HUB, class 9/0, rev 1.00/1.00, addr 1> on usbus1
>> ugen2.1: <Intel> at usbus2
>> uhub2: <Intel UHCI root HUB, class 9/0, rev 1.00/1.00, addr 1> on usbus2
>> ugen3.1: <Intel> at usbus3
>> uhub3: <Intel UHCI root HUB, class 9/0, rev 1.00/1.00, addr 1> on usbus3
>> ugen4.1: <Intel> at usbus4
>> uhub4: <Intel EHCI root HUB, class 9/0, rev 2.00/1.00, addr 1> on usbus4
>> Root mount waiting for: usbus4
>> Root mount waiting for: usbus4
>> Root mount waiting for: usbus4
>> Root mount waiting for: usbus4
>> ugen4.2: <USB 2.0> at usbus4
>> umass0: <USB 2.0 Flash Disk, class 0/0, rev 2.00/1.00, addr 2> on usbus4
>> Root mount waiting for: usbus4
>> pass3: <USB 2.0 Flash Disk 5.00> Removable Direct Access SCSI-2 device
>> da0: <USB 2.0 Flash Disk 5.00> Removable Direct Access SCSI-2 device
>> Root mount waiting for: usbus4
>> ugen1.2: <vendor 0x1941> at usbus1
>> ugen1.3: <vendor 0x04f9> at usbus1
>> ulpt0: <vendor 0x04f9 product 0x0100, class 0/0, rev 1.00/1.00, addr
>> 3> on usbus1
>> ugen2.2: <Logitech> at usbus2
>> uhub5: <Logitech Logitech BT Mini-Receiver, class 9/0, rev 2.00/49.00,
>> addr 2> on usbus2
>> ugen2.3: <Logitech> at usbus2
>> ukbd0: <Logitech Logitech BT Mini-Receiver, class 0/0, rev 2.00/49.00,
>> addr 3> on usbus2
>> ugen2.4: <Logitech> at usbus2
>> ums0: <Logitech Logitech BT Mini-Receiver, class 0/0, rev 2.00/49.00,
>> addr 4> on usbus2
>> ---snip---
>
> Hi,
>
> If you dump all threads in this state I think you will see that USB  
> is waiting

# procstat -kk 29213
   PID    TID COMM             TDNAME           KSTACK
29213 100291 usbconfig        -                mi_switch+0x188  
sleepq_switch+0x13c sleepq_timedwait+0x40 _sleep+0x320 pause+0x30  
usb_pause_mtx+0x94 usb_ioctl+0x171 devfs_ioctl_f+0x73 kern_ioctl+0x9d  
ioctl+0xc5 syscallenter+0x1af syscall+0x34 Xint0x80_syscall+0x21

> somewhere in umass_detach(), which is preventing the usbconfig reset from

No umass_detach in there...

> grabbing the SX-lock associated with serialisation. Because umass_detach() is
> not returning we are stuck.

And there is no way to use some kind of timeout for cases which cause  
problem reports (like umass_detach() and maybe this one)? I could  
imagine several possibilities: usbconfig tries a trylock first (maybe  
several times) and if it does not succeed in a specified timeperiode,  
it returns an error. Adidtionally there is maybe the possibility to  
determine if a command did not finish in a given timeperiode and print  
out a warning message (syslog) to have an indication, that somthing is  
not in a good condition.

Bye,
Alexander.

-- 
I hate small towns because once you've seen the cannon in the park
there's nothing else to do.
		-- Lenny Bruce

http://www.Leidinger.net    Alexander @ Leidinger.net: PGP ID = B0063FE7
http://www.FreeBSD.org       netchild @ FreeBSD.org  : PGP ID = 72077137