Panic in usb_unref_device

[Daniel O'Connor]

Hi,
I have a custom USB device based on the Cypress FX2 and we are finding that with some older kernels it hangs - this was fixed in https://svnweb.freebsd.org/base?view=revision&revision=267240 but now it panics with…

#7  0xffffffff80745a07 in usb_unref_device (cpd=0xfffffe0004b30680, crd=0xffffff812b6af860) at /usr/src/sys/dev/usb/usb_dev.c:348
#8  0xffffffff80748cbd in usb_ioctl (dev=<value optimized out>, cmd=3222040644, addr=0xfffffe0026380000 "\002", fflag=<value optimized out>, td=0xffffffff81819850)
   at /usr/src/sys/dev/usb/usb_dev.c:1127
#9  0xffffffff807d05cb in devfs_ioctl_f (fp=0xfffffe0061d59190, com=3222040644, data=<value optimized out>, cred=<value optimized out>, td=0xfffffe0004e37920)
   at /usr/src/sys/fs/devfs/devfs_vnops.c:758
#10 0xffffffff80938456 in kern_ioctl (td=0xfffffe0004e37920, fd=3, com=3222040644, data=0xfffffe0026380000 "\002") at file.h:311
#11 0xffffffff8093869d in sys_ioctl (td=0xfffffe0004e37920, uap=0xffffff812b6afa70) at /usr/src/sys/kern/sys_generic.c:696

And crd->rxfifo is NULL.

I haven’t looked very hard at this yet, but it is quite easy to reproduce.

--
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C