Hello, I am also affected by this same bug.
I run Firefox in a virtual machine and if I am running the 5.10.0-15-amd64 kernel on the virtual host, then Firefox crashes regularly in the virtual guest. However, if I run the 5.10.0-14-amd64 kernel on the virtual host, then I see no crashes. In both cases the virtual guest is running the 5.10.0-15-amd64 kernel This is on Debian Bullseye VirtualBox packages are from Fasttrack virtualbox 6.1.34-dfsg-3~fto11+1 amd64 virtualbox-dkms 6.1.34-dfsg-3~fto11+1 amd64 virtualbox-qt 6.1.34-dfsg-3~fto11+1 amd64 Kernels are the standard Debian kernels from stable (both host and guest) linux-image-5.10.0-14-amd64 5.10.113-1 amd64 linux-image-5.10.0-15-amd64 5.10.120-1 amd64 I have seen this issue on two separate systems, so I do not think it is hardware related. Happy to do any testing or provide any logs you can suggest. Regards, Richard
