[Bug 285867] 14.2-RELEASE kernel hangs on Thinkpad T400

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=285867

Tomoaki AOKI <junchoon@dec.sakura.ne.jp> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |junchoon@dec.sakura.ne.jp

--- Comment #4 from Tomoaki AOKI <junchoon@dec.sakura.ne.jp> ---
Read your post at freebsd-stable ML.

Quite wild prediction, but are you loading any kmods, especially GPU-related
ones from non-base (ports/pkgs or building directly from upstream codes), in
your /boot/loader.conf?

If yes, and if the kmod is NOT clearly essential for FreeBSD to boot (i.e.,
disk controller driver, but unlikely for ThinkPads with Intel or AMD CPUs),
move them to kld_list variable in /etc/rc.conf[.local].
Note that GPU drivers are not at all essential to boot FreeBSD base itself.

A bit of details:
kmods loaded via kld_list, autoloading via devd and/or manual loading with
kldload is done under control of kernel. And kernel checks the kmods to be
compatible with itseld or not on loading.

But loading via /boot/loader.conf is different.

loader loads kernel and kmods specified in /boot/loader.conf into staging area
it allocated before hand-over to kernel. And loader is not aware of the version
of the kernel and kmods. So incompatible kmods can be loaded, thus, causing
problems.
And as the staging area is limited, anything not fitting in it are forcibly
truncated, causing undefined behaviors.

And single user mode is the mode that anything in /etc and/or in
/usr/local/etc, including network, fstab,... is not yet initialized. Loaded
modules via /boot/loader,conf affects here, too.

IIUC, safe mode disables some options/funtionalities that are known to cause
problems in certain cases. So this could (not always assured, though) avoid
problematic kmods to be loaded, thus, allowed you to boot.

-- 
You are receiving this mail because:
You are the assignee for the bug.