Re: 15.0-RELEASE boot panic when if_iwm_load="YES"

On Sat, 29 Nov 2025, at 16:00, Karlo Miličević wrote:
> I know 15.0 is not released yet but the image is up and I wanted to try 
> it out on real hardware.
>
> After I put if_iwm_load="YES" in /boot/loader.conf it fails to boot.
> After saying it's loading loader.conf and briefly flashing FreeBSD logo 
> I get a panic:
>
> panic: page fault
> cpuid = 0
> time = 1
> KDB: stack backtrace:
> #0 0xffffffff80bbe1ed at kdb_backtrace+0x5d
> #1 0xffffffff80b71576 at vpanic+0x136
> #2 0xffffffff80b71433 at panic+0x43
> #3 0xffffffff81079f69 at trap_pfault+0x3c9
> #4 0xffffffff8104ff18 at calltrap+0x8
> #5 0xffffffff80c4f974 at namei+0xe4
> #6 0xffffffff80c768b2 at vn_open_cred+0x5b2
> #7 0xffffffff80bb9ef4 at loadimage+0x274
> #8 0xffffffff80bd4de2 at taskqueue_run_locked+0x182
> #9 0xffffffff80bd5fb2 at taskqueue_thread_loop+0xc2
> #10 0xffffffff80b2786b at fork_exit+0x7b
> #11 0xffffffff81050f3e at fork_trampoline+0xe
> Uptime: 1s
> Automatic reboot in 15 seconds - press a key on the console to abort
>
> Am I doing something wrong?
> IIRC this worked on 14.3 on the same hardware.

Hi Karlo

I can't speak for the panic, but these other tips may help.

Make sure you've got the relevant firmware - boot with iw_iwm disabled
(see below if devmatch attaches it automatically), and run `fwget`,
it should do the right thing even if the driver isn't loaded:

# fwget
Needed firmware packages: 'wifi-firmware-mt76-kmod-mt792x ...
The most recent versions of packages are already installed

The 15.0-RELEASE tag is already in sources, and signed, so there's
nothing release-specific we can do at this stage.

You can try using the /latest/ FreeBSD ports tree (or via packages)
and make sure your intel firmware bundle is updated.

I don't know what hardware you have, but if it's supported by
https://man.freebsd.org/iwlwifi then you can try that as an alternative,
it's seen a lot of development during the last few months. 

It's probably more convenient to late-load via rc.conf:

devmatch_blocklist="if_iwmn"
kld_list="${kld_list} if_iwlwifi"

This prevents the iwm driver being attached, and prefers the newer one
instead.

There is also https://man.freebsd.org/if_iwx with overlapping hardware
support.

In either case, thanks for testing, and consider logging a PR after
checking https://wiki.freebsd.org/WiFi/Iwlwifi#testing & seeing
if your issue is already reported in the meta-bug at https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=273620

There is a freebsd-wireless@freebsd.org list too.

I believe both 16-CURRENT and 15-STABLE have some new bits too already,
so that may be worth a try as a final resort.

A+
Dave