a recent update to virt-preview started to cause my guest vm crash early in booting. I'm running fedora 42 on the host and guest. I've been using virt-preview for years and this is the first time it has giving me an issue. I think this is a regression. I can only boot my guest vm if i disable 3dacc and OpenGL. and even then i still have graphic issues with firefox and chrome crashing playing videos in the running guest. I've downgraded to fedora 42 repository qemu, libvirt and other related products and i have no issues with crashes during boot and in the guest VM, firefox and chrome no longer crash playing videos. I have lots of core dumps of qemu-system-x86_64 and i will attach a few. more info about my vm host: Operating System: Fedora Linux 42 KDE Plasma Version: 6.4.4 KDE Frameworks Version: 6.17.0 Qt Version: 6.9.1 Kernel Version: 6.16.3-200.fc42.x86_64 (64-bit) Graphics Platform: Wayland Processors: 16 × AMD Ryzen 7 9700X 8-Core Processor Memory: 128 GiB of RAM (123.4 GiB usable) Graphics Processor: AMD Radeon Graphics Manufacturer: ASRock Product Name: X870E Taichi the guest is running the same fedora version and kernel version. Reproducible: Always Steps to Reproduce: 1. use virt-preview and install qemu, libvirt and other required components 2. create a fedora 42 or rawhide guest 3.in the guest, enable 3d acceleration and OpenGL 4. Start the guest and very early in the boot, it crashes Actual Results: crashes with 3d acceleration and OpenGL enable. with them disabled it will boot but video on the guest is not stable. Expected Results: seem to be a regression in the release canidate I tried to get a kdump but it the crash occurs too soon in the boot for kdump to catch a core.
Created attachment 2105045 [details] stack of crashed qemu-system
Created attachment 2105046 [details] stack of crashed qemu
Rather than attaching core dumps, much more useful would be stack traces. Use 'coredumpctl gdb' and in gdb run the command 't a a bt'.
i'm not sure this stack trace is more useful than the decompressed zstd file but i'm attaching. It looks like there are symbols missing in the gdb stack. I've included the whole coredumpctl term session Let me know if you need anything else.
Created attachment 2105048 [details] gdb stack output
oh i forgot, i have downgraded from the preview version so i dont' have those debuginfo files there so the trace stack won't be correct now.
> oh i forgot, i have downgraded from the preview version so i dont' have those debuginfo files there so the trace stack won't be correct now. I'm unclear what this means exactly, but we'd definitely prefer if we have full debuginfo installed that exactly corresponds to the qemu version where the crash occurred, and then get the stack trace with full symbols. It may be necessary to reproduce the crash again to be really sure everything is lined up properly. Otherwise we'd be wasting time chasing shadows.
Created attachment 2105056 [details] gdb stack trace
Created attachment 2105057 [details] 2nd gdb stack trace
I upgraded to the preview version, installed debuginfo rpms and reproduced the problem. I've extracted the gdb trace stack info and attached to the bug. These stack traces look readable.
Unfortunately there are still missing debug symbols. See the suggested command to run in the output linked in comment 9.
Created attachment 2105108 [details] gdb stack trace replacing the attachments with update stack trace
Created attachment 2105109 [details] gcb stack trace with more debuginfo
sorry i missed that info in the coredump. I've installed all the debuginfo except for libxdp-debuginfo-1.5.6-1.fc42.x86_64 this doesn't exist anywhere in any of the fedora repositories that i know about.
The following changes to spice were in qemu 10.1.0 0c0729b46a3680c233e0d45647d5193c5c5083f9 ui/spice: Destroy the temporary egl fb after the blit is submitted f851cd65ebe24cc716a70a2fa68c149e5440f2f4 ui/spice: Blit the scanout texture if its memory layout is not linear 2103690b1a7d98f88f7c150f48fcd951d3ee8b36 ui/spice: Create a new texture with linear layout when gl=on is specified 50d135e3779f276eba93c63dff49a940b85e23a5 ui/spice: Add an option to submit gl_draw requests at fixed rate 376d4b22e4d7dd81cb0c1ea1dfe1db0a0dc4b0e2 ui/spice: Enable gl=on option for non-local or remote clients 98a050ca93afd8686b78c3a71cbeef23e0bc420b ui/spice: support multi plane dmabuf scanout 0e15d0b92700000db66e19c68ad2d50aace860d8 ui/egl: support multi-plane dmabuf when egl export/import bb5101aadc1675790983c7911092dd9abeec4651 ui/dmabuf: extend QemuDmaBuf to support multi-plane given the stack trace it is strongly pointing to 98a050ca93afd8686b78c3a71cbeef23e0bc420b being flawed.
@marcandre: could you take a look at the stack trace and see if you can spot what might be wrong with the spice commits above
Created attachment 2105121 [details] potential fix @mark, can you try this patch?
Hi, I'd be happy to try the patch but i can't accesss the attachement Sorry, you are not authorized to access attachment #2105121 [details].
You should be able to access it now.
still getting a not authorized to access. security is never easy ;)
I see the patch now. I can't do that as i'm not building from source. If you can get me a new binary i can replace just that instead of someone building a new install package (rpm)
Comment on attachment 2105121 [details] potential fix i see there is a new build for 10.1.0-5. is this patch in that build? if so i can wait for it to show up in the preview repository.
i can confirm that the fix is not in 10.1.0-5. If someone can make available a patched library/executable i'll be happy to test. I do not have a build/dev env where i can patch source code.
Try with this scratch-build: https://koji.fedoraproject.org/koji/taskinfo?taskID=136509748 (hmm I should have used a different version/suffix..)
I was finally able to test the patch and yes it does resolve the crash during boot. I'm now running a guest VM to see if it also fixes the issue with firefox and chrome crashes during video playback.
FEDORA-2025-b8b6acb283 (qemu-10.1.0-6.fc43) has been submitted as an update to Fedora 43. https://bodhi.fedoraproject.org/updates/FEDORA-2025-b8b6acb283
FEDORA-2025-b8b6acb283 has been pushed to the Fedora 43 testing repository. Soon you'll be able to install the update with the following command: `sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2025-b8b6acb283` You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2025-b8b6acb283 See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.
FEDORA-2025-b8b6acb283 (qemu-10.1.0-6.fc43) has been pushed to the Fedora 43 stable repository. If problem still persists, please make note of it in this bug report.