Panic in ugen_detach

[Tilman Linneweh]

Hi,

Today i disconnected my Webcam (Creative Vista), while the device was still 
opened by spcaview.

It resulted in a panic with the following trace:

#6  0xffffffff8043dee1 in trap (frame=
      {tf_rdi = -1099208402944, tf_rsi = -2140788064, tf_rdx = 1, tf_rcx = 
-2140672512, tf_r8 = -2140227616, tf_r9 = -2140672512, tf_rax = 35, tf_rbx = 
-2401050962867404578, tf_rbp = -1522521440, tf_r10 = 0, tf_r11 = 4, tf_r12 = 
-1099208402944, tf_r13 = 16, tf_r14 = -2047905792, tf_r15 = -1098479267120, 
tf_trapno = 9, tf_addr = 0, tf_flags = -2142535890, tf_err = 0, tf_rip = 
-2144905637, tf_cs = 8, tf_rflags = 66182, tf_rsp = -1522521456, tf_ss = 16})
    at /usr/src/sys/amd64/amd64/trap.c:490
#7  0xffffffff8042c5bb in calltrap ()
    at /usr/src/sys/amd64/amd64/exception.S:168
#8  0xffffffff8027565b in devtoname (dev=0xffffff001212d800)
    at /usr/src/sys/kern/kern_conf.c:708
#9  0xffffffff802757df in destroy_devl (dev=0xffffff001212d800)
---Type <return> to continue, or q <return> to quit---
    at /usr/src/sys/kern/kern_conf.c:663
#10 0xffffffff80275935 in destroy_devl (dev=0xffffff00246c6000)
    at /usr/src/sys/kern/kern_conf.c:652
#11 0xffffffff80275a89 in destroy_dev (dev=0xffffff00246c6000)
    at /usr/src/sys/kern/kern_conf.c:697
#12 0xffffffff80235c85 in ugen_detach (self=0xffffff001212d800)
    at /usr/src/sys/dev/usb/ugen.c:1035
#13 0xffffffff802ba11a in device_detach (dev=0xffffff001a16bb00)
    at device_if.h:211
#14 0xffffffff802468cd in usb_disconnect_port (up=0xffffff0000b84a38,
    parent=0xffffff001212d800) at /usr/src/sys/dev/usb/usb_subr.c:1437
#15 0xffffffff8023c88a in uhub_explore (dev=0xffffff003d8eab00)
    at /usr/src/sys/dev/usb/uhub.c:465
#16 0xffffffff80243167 in usb_discover (v=0xffffff001212d800)
    at /usr/src/sys/dev/usb/usb.c:747
#17 0xffffffff802431d8 in usb_event_thread (arg=0xffffff001212d800)
    at /usr/src/sys/dev/usb/usb.c:433
#18 0xffffffff8028931b in fork_exit (
    callout=0xffffffff80243180 <usb_event_thread>, arg=0xffffff003d865280,
    frame=0xffffffffa5402c90) at /usr/src/sys/kern/kern_fork.c:790

This is CURRENT amd64 from November 22

regards
tilman