Armv7 (rpi2) getting stuck in buildworld for -current

Lately a Pi2 running -current has gotten stuck while buildworld is running.
There's no escape to debugger, no obvious errors on the console and only
modest swap use (tens of MB). So far the stoppages have been when building
clang.

One possible culprit is /boot/loader.conf, which has accumulated some baggage
over the years:

bob@www:/usr/src % more /boot/loader.conf
# Configure USB OTG; see usb_template(4).
hw.usb.template=3
umodem_load="YES"
# Disable the beastie menu and color
beastie_disable="YES"
loader_color="NO"
vm.pageout_oom_seq="4096"
#vm.pfault_oom_attempts="3"
vm.pfault_oom_attempts="120"
vm.pfault_oom_wait="20"
kern.cam.boot_delay="20000"
vfs.ffs.dotrimcons="1"
vfs.root_mount_always_wait="1"
filemon_load="YES"
net.inet.tcp.tolerate_missing_ts="1"
vm.swap_enabled=0
vm.swap_idle_enabled=0
--More--(END)

However, the problem emerged well after the changes above were made.


A running diary of experiments is at
http://www.zefox.net/~fbsd/rpi2/crashes/20230514/armv7hang

Thanks for reading,

bob prohaska