From: Larry Finger <Larry.Finger@lwfinger.net>
To: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: Changes in kernel 5.18-rc1 leads to crashes in VirtualBox Virtual Machines
Date: Sun, 1 May 2022 12:26:07 -0500 [thread overview]
Message-ID: <7f01221d-f693-adf8-f5a5-d71944b44162@lwfinger.net> (raw)
Jason,
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,
Larry
next reply other threads:[~2022-05-01 17:26 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-01 17:26 Larry Finger [this message]
2022-05-01 17:47 ` Changes in kernel 5.18-rc1 leads to crashes in VirtualBox Virtual Machines Jason A. Donenfeld
2022-05-01 21:07 ` Larry Finger
2022-05-01 23:32 ` Jason A. Donenfeld
2022-05-02 0:11 ` Jason A. Donenfeld
2022-05-02 1:05 ` Jason A. Donenfeld
2022-05-02 10:49 ` Jason A. Donenfeld
[not found] <SJ0PR10MB5742C02D9F7F146A1313BD5DE9CE9@SJ0PR10MB5742.namprd10.prod.outlook.com>
2022-05-17 18:33 ` Larry Finger
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=7f01221d-f693-adf8-f5a5-d71944b44162@lwfinger.net \
--to=larry.finger@lwfinger.net \
--cc=Jason@zx2c4.com \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).