Re: [Qemu-devel] Guests are crashing on startup, seem related to usb-audio

[Leonardo Soares Müller]

I am testing this QEMU build in two VM guests, one Mageia 7 and other
openSUSE Leap. They reach the graphical session, play a sound using
aplay and reboot automatically. The screen and audio from the host were
captured to check if the sound would work even with the warning.

Once, the Mageia 7 guest had in the terminal:

qemu-system-x86_64: warning: usb-audio: 0/192

And it continued operating normally, with no crash or freeze and sound
played normally. One video showing its behavior can be seen on this link:

https://cdn.discordapp.com/attachments/457747189616214019/521744887192879120/qemu-teste-audio002.webm

The sound quality in the video is worse than normal because the Mageia
guest sample rate is set to 44100 Hz while the usb-audio sample rate is
48000 Hz and because FFmpeg "magnifies" certain audio issues.

The openSUSE guest has once shown the following:

qxl_send_events: spice-server bug: guest stopped, ignoring
[Thread 0x7fffcf7fe700 (LWP 12771) exited]
[New Thread 0x7fffcf7fe700 (LWP 13036)]
[Thread 0x7fffcf7fe700 (LWP 13036) exited]
[New Thread 0x7fffcf7fe700 (LWP 13067)]
[Thread 0x7fffcf7fe700 (LWP 13067) exited]
[New Thread 0x7fffcf7fe700 (LWP 13098)]
qemu-system-x86_64: warning: usb-audio: 0/192
qemu-system-x86_64: warning: usb-audio: 0/192
qemu-system-x86_64: warning: usb-audio: 0/192
qemu-system-x86_64: warning: usb-audio: 0/192
qemu-system-x86_64: warning: usb-audio: 0/192
qemu-system-x86_64: warning: usb-audio: 0/192
qemu-system-x86_64: warning: usb-audio: 0/192
qemu-system-x86_64: warning: usb-audio: 0/192
qemu-system-x86_64: warning: usb-audio: 0/192
qemu-system-x86_64: warning: usb-audio: 0/192

While it did not crash, its screen froze. By the QXL message, it seems
the bug https://bugs.launchpad.net/qemu/+bug/1787070 is still present
and causing failures on guests too, with openSUSE still being the
biggest victim.

Regarding this specific usb-audio crash problem, QEMU from
sirius/usb-audio-crash seems to be fixed.

Às 10:56 de 10/12/2018, address@hidden escreveu:
> On Mon, Dec 10, 2018 at 12:11:09PM +0000, Leonardo Soares Müller wrote:
>> Hi, I did not save that Mageia 7 data as I was unaware I could do this.
>> The data below is from another crash with openSUSE Leap, this time I
>> saved this backtrace with generate-core-file.
> 
>> On #4 it shows:
>> $2 = {pid = 225, id = 2027203168, ep = 0x555557e46520, stream = 0, iov =
>> {iov = 0x7fffc418d190, niov = 0, nalloc = 1, size = 0}, parameter = 0,
>                                                ^^^^^^^^
>> short_not_ok = false, int_req = false, status = 0, actual_length = 0,
>>   state = USB_PACKET_SETUP, combined = 0x0, queue = {tqe_next = 0x0,
>> tqe_prev = 0x0}, combined_entry = {tqe_next = 0x0, tqe_prev = 0x0}}
> 
> Hmm, zero-length usb package.  Should be 192 bytes ...
> 
> Does anything change with
>   https://git.kraxel.org/cgit/qemu/log/?h=sirius/usb-audio-crash ?
> 
> thanks,
>   Gerd
>