[Qemu-devel] [BUG] USB assertion triggers in usb_packet_complete()

[Thomas Huth]

 Hi!

I am currently facing a problem when running QEMU (up-to-date git
version) with OHCI and a lot of virtual USB devices.
The emulator dies with the following assertion:

qemu-system-arm: hw/usb.c:337: usb_packet_complete:
Assertion `p->owner != ((void *)0)' failed.

To reproduce this problem, you can run the configure script with
"--target-list=arm-softmmu" for example, then download the files
vmlinuz-2.6.26-2-versatile and initrd.img-2.6.26-2-versatile
from http://people.debian.org/~aurel32/qemu/arm/ and then run
qemu like this:

qemu-system-arm -kernel vmlinuz-2.6.26-2-versatile \
  -initrd initrd.img-2.6.26-2-versatile -M versatilepb -usb \
  -drive if=none,file=/tmp/linux-0.2.img,cache=none,id=disk0 \
  -device usb-storage,drive=disk0 -usbdevice mouse \
  -usbdevice keyboard -usbdevice tablet

It boots the Linux kernel for a while, then dies with the above
assertion.

Observations:
- It could be related to the fact that QEMU puts a hub into the
  USB tree in that case ... when I specify less USB devices, I was
  not able to reproduce this problem, but in that case there are
  also no hubs in the tree. According to the comment in
  usb_packet_complete(), there might be problems with the assert() in
  case there is a hub ... ?
- So far I was only able to reproduce this problem when the emulated
  platform uses an OHCI controller. I haven't seen the problem to
  occur with UHCI yet (but I have to admit that I also haven't done a
  lot of tests with UHCI).

Do you have any ideas what could be wrong here?

 Regards,
  Thomas