kern/48987: Kernel crashes on using ATmega32u4 Arduino on USB

[ddeus.netbsd%mailnull.com@localhost]

>Number:         48987
>Category:       kern
>Synopsis:       Kernel crashes on using ATmega32u4 Arduino on USB
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Jul 12 11:25:00 +0000 2014
>Originator:     Oleksandr Kozachuk
>Release:        CURRENT
>Organization:
>Environment:
NetBSD iridium.kozachuk.info 6.99.46 NetBSD 6.99.46 (GENERIC) #1: Tue Jul  8 
20:06:36 CEST 2014  
root%bohrium.kozachuk.info@localhost:/usr/obj/amd64/sys/arch/amd64/compile/GENERIC
 amd64

>Description:
If I plugin my ATmega32u4 Arduino on the USB (I have a Arduino Pro Micro), then 
often, f.e. on reset of arduino board or on detaching, the kernel crashes 
often, f.e. with following backtrace:

#0  0xffffffff805b14c5 in cpu_reboot (howto=howto@entry=260, 
bootstr=bootstr@entry=0x0) at /usr/src/sys/arch/amd64/amd64/machdep.c:671
#1  0xffffffff807a83d4 in vpanic (fmt=0xffffffff80b9db18 "kernel %sassertion 
\"%s\" failed: file \"%s\", line %d ", ap=ap@entry=0xfffffe810e622c28) at 
/usr/src/sys/kern/subr_prf.c:284
#2  0xffffffff80932cc3 in kern_assert (fmt=fmt@entry=0xffffffff80b9db18 "kernel 
%sassertion \"%s\" failed: file \"%s\", line %d ") at 
/usr/src/sys/lib/libkern/kern_assert.c:51
#3  0xffffffff80936b2c in cv_exit (l=<optimized out>, error=0, 
mtx=0xffff80000e5ee4a8, cv=0xfffffe810e580cd8) at 
/usr/src/sys/kern/kern_condvar.c:177
#4  0xffffffff805185c1 in cv_exit (l=<optimized out>, error=0, 
mtx=0xffff80000e5ee4a8, cv=0xfffffe810e580cd8) at 
/usr/src/sys/kern/kern_condvar.c:220
#5  cv_wait (cv=cv@entry=0xfffffe810e580cd8, mtx=mtx@entry=0xffff80000e5ee4a8) 
at /usr/src/sys/kern/kern_condvar.c:219
#6  0xffffffff80662712 in ohci_abort_xfer (xfer=0xfffffe810e580c30, 
status=USBD_CANCELLED) at /usr/src/sys/dev/usb/ohci.c:2330
#7  0xffffffff80870f37 in usbd_ar_pipe (pipe=0xfffffe82156aff18) at 
/usr/src/sys/dev/usb/usbdi.c:768
#8  usbd_abort_pipe (pipe=0xfffffe82156aff18) at 
/usr/src/sys/dev/usb/usbdi.c:560
#9  0xffffffff8081a6c8 in ucom_detach (self=0xfffffe82170909c8, 
flags=<optimized out>) at /usr/src/sys/dev/usb/ucom.c:274
#10 0xffffffff8079244d in config_detach (dev=0xfffffe82170909c8, flags=1) at 
/usr/src/sys/kern/subr_autoconf.c:1689
#11 0xffffffff80865acf in umodem_common_detach (sc=0xfffffe821b60ac00, 
flags=<optimized out>) at /usr/src/sys/dev/usb/umodem_common.c:677
#12 0xffffffff8079244d in config_detach (dev=dev@entry=0xfffffe8212491388, 
flags=flags@entry=1) at /usr/src/sys/kern/subr_autoconf.c:1689
#13 0xffffffff808705ea in usb_disconnect_port (up=up@entry=0xfffffe810e5cff88, 
parent=<optimized out>, flags=flags@entry=1) at 
/usr/src/sys/dev/usb/usb_subr.c:1601
#14 0xffffffff808426e8 in uhub_explore (dev=0xfffffe810e54b890) at 
/usr/src/sys/dev/usb/uhub.c:490
#15 0xffffffff8086cfc5 in usb_discover (sc=0xfffffe810e249048, 
sc=0xfffffe810e249048) at /usr/src/sys/dev/usb/usb.c:829
#16 0xffffffff8086d086 in usb_event_thread (arg=0xfffffe810e249048) at 
/usr/src/sys/dev/usb/usb.c:411
#17 0xffffffff80100807 in lwp_trampoline ()
#18 0x0000000000000000 in ?? ()


>How-To-Repeat:
Connect the ATmega32u4 to the machine and press reset.
>Fix: