USB serial device passtrough causes qemu to segfault and kill the VM
| Affects | Status | Importance | Assigned to | Milestone | |
|---|---|---|---|---|---|
| qemu (Ubuntu) |
Expired
|
Undecided
|
Unassigned | ||
Bug Description
What happens:
When I pass trough my CH340G (very common USB-TTL serial module) with high-baud data coming in to my Windows 10 VM. qemu segfaults and dirtily shuts down my VM at some random point. The higher the baudrate, the more likely it is to happen. 921600 means the death to my VM in somewhere between 10 seconds and a few minutes. There's no blue screen or anything, it's qemu dying and taking the VM with it.
So far I've also determined:
* It does not crash as often on lower baudrates.
* It does not seem to crash if there's no data coming in.
* It does not matter if something is reading the data or not.
* It does not matter what software is reading the serial device.
What should happen:
Qemu shouldn't crash on a device being passed trough.
System details:
Host - Ubuntu 20.04, qemu-system-common 4.2-3ubuntu6.1 (and everything else as well latest from repository)
VM - Windows 10, latest updates installed
Diagnostics info:
dmesg output:
[19511.277076] qemu-system-
[19511.277082] Code: a8 02 75 34 48 8b 15 f5 d4 14 00 64 48 83 3a 00 0f 84 9a 00 00 00 48 8d 3d eb e2 14 00 a8 04 74 0c 48 89 f0 48 25 00 00 00 fc <48>
8b 38 31 d2 48 83 c4 18 e9 10 c1 ff ff 8b 15 fe d9 14 00 85 d2
lsusb output (this is a CH340G module, very very widespread and cheap):
Bus 002 Device 018: ID 0403:6001 Future Technology Devices International, Ltd FT232 Serial (UART) IC
| Rafael David Tinoco (rafaeldtinoco) wrote | #1 |
| Changed in qemu (Ubuntu): | |
| status: | New → Incomplete |
| Launchpad Janitor (janitor) wrote | #2 |
| Changed in qemu (Ubuntu): | |
| status: | Incomplete → Expired |
@avamander,
Thank you for taking the time to file a bug report.
Could you provide the libvirt domain XML file you're using to start your qemu instance ? Would you be able to reproduce this issue and generate a core file from your host's qemu process and provide it to us ? Or, at least, provide us a detailed reproducer so we can reproduce it on our side ?
Since there is not enough information in your report to begin triage or to
differentiate between a local configuration problem and a bug in Ubuntu, I
am marking this bug as "Incomplete". We would be grateful if you would:
provide a more complete description of the problem, explain why you
believe this is a bug in Ubuntu rather than a problem specific to your
system, and then change the bug status back to "New".
For local configuration issues, you can find assistance here:
http://