Re: Panic (page fault) on boot after update to main-n290177-6866177454ac

On Sat, Oct 17, 2026 at 09:42:33AM -0700, David Wolfskill wrote:
> ...
> One, however, built OK, but on reboot, started coming up, but
> apparently did not succeed in switching video modes -- while normally,
> I expect the screen to blank, then resume the display of various
> kernel messages, it went blank ... and didn't bring up the (iwlwifi(4))
> link.  (This is the only one of the machines that uses iwlwifi(4).)
> ....

Slightly different approach yielding apparently similar results, but
with more information:

I found that if I commented out the 

	kld_list="i915kms"

line in /etc/rc.conf, the machine boots the current kernel & userland
OK -- it just doesn't switch to graphics mode (so xdm doesn't come up).

Then, if I subsequently login & issue "sudo kldload i915kms", I get the
screen going "blank" (as before, as far as I can tell).

Following a suggestion from bz@, I went ahead and:
* Waited about a minute or so;
* Blind-typed "dump";
* Waited for another couple of minutes;
* Blind-typed "reset"

and the machine rebooted.  And it found a crasah dump. :-}

Turns out I didn't have gdb installed, so I installed it, then ran
crashinfo manually to put something useful in core.txt.0.

I have now placed a copy of the crash dump and the core.txt.0, as well
as gzipped copies of each, in
https://www.catwhisker.org/~david/FreeBSD/head/n290177/

albert(15.1-S)[16] ls -lTh
total 1.1 GB
-rw-r--r--  1 david staff  116K Oct 17 14:38:57 2026 core.txt.0
-rw-r--r--  1 david staff   21K Oct 17 14:38:57 2026 core.txt.0.gz
-rwxr-xr--  1 david staff  2.8M Oct 17 09:22:56 2026 crash.jpg
-rw-r--r--  1 david staff  1.2G Oct 17 14:31:41 2026 vmcore.0
-rw-r--r--  1 david staff  509M Oct 17 14:31:41 2026 vmcore.0.gz

This is on a residential ADSL connection, so the gzipped copies are more
likely to be useful.

The panic string showin in core.txt.0 is, however, a bit different from
the initially-reported one:

FreeBSD g1-129.catwhisker.org 16.0-CURRENT FreeBSD 16.0-CURRENT #57 main-n290177-6866177454ac: Sat Oct 17 12:44:41 UTC 2026     root@g1-129.catwhisker.org:/usr/obj/usr/src/amd64.amd64/sys/GENERIC  amd64

panic: Unrecoverable machine check exception


As before, I am willing to experiment, given suitable clues.

Peace,
david
-- 
David H. Wolfskill                              david@catwhisker.org

See https://www.catwhisker.org/~david/publickey.gpg for my public key.