[lkml]   [2022]   [May]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectChanges in kernel 5.18-rc1 leads to crashes in VirtualBox Virtual Machines

I maintain VirtualBox for openSUSE. When kernel 5.18-rc1 was released, I fixed
the usual set of API changes needed to compile the external kernel modules for
VB. Despite a clean compile, I am still getting random crashes in the VMs. For
Linux instances, the desktop disappears, but for Windows guests, the VM crashes
with unhandled kernel exceptions. As I have no experience tracing such crashes,
I decided to bisect the kernel to find the commit that started these problems.

Surprisingly, the bisection pointed to commit 6e8ec2552c7d ("random: use
computational hash for entropy extraction"). I am very sure of the bisection as
the kernel built from the commit that immediately precedes this one,
cfb92440ee71 - a tag commit by Linus, runs correctly.

Note that I do not believe there is anything wrong with your changes to the
random number generators. It seems to be a problem with the way the emulator is
accessing them. The VirtualBox code is quite complicated, and I am no expert
with C++.

Are there changes that would be required to the X86_64 emulator's access to the
random number code as a result of your changes? I have found places where the
emulator accesses /dev/urandom or /dev/random. There are also places that use
the rdrand and reseed instructions.

Thanks for reading this,


 \ /
  Last update: 2022-05-01 19:27    [W:0.055 / U:0.532 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site