Something seems weird at main-n287304-8a14fcd23a20

In-place source-based update from:

FreeBSD 16.0-CURRENT #626 main-n287257-849a51ac8371: Tue Jul  7 11:55:43 UTC 2026     root@freebeast.catwhisker.org:/common/S4/obj/usr/src/amd64.amd64/sys/GENERIC amd64 1600019 1600019

to:

FreeBSD 16.0-CURRENT #627 main-n287304-8a14fcd23a20: Wed Jul  8 11:08:41 UTC 2026     root@freebeast.catwhisker.org:/common/S4/obj/usr/src/amd64.amd64/sys/GENERIC amd64 1600019 1600019

seemed to be uneventful.

But then, after having run "make delete-old-libs", I tried to use scp to
copy some files over to my Web server (for reference); the copy started,
then stalled (without actually copying anything), and eventually timed
out.  This machine uses a wired NIC (em(4)), which has been ... boringly
reliable in the past years....

And then a laptop (that I was updating in parallel, and which uses a
wireless (iwn(4)) NIC, exhibited similar (the same?) symptoms.  And in
its case (as well as another laptop), it claims xdm is running (as it
should be), but the screen is either blank or black-on-black.  Using
Ctl-Alt-F2 gets to a login prompt on ttyv1, as usual.

I just tried using scp on another (smaller) file, which worked.
And a third file, which started, then reported "scp: Connection
closed" without actualy copying anything.

So... I just set up an odd little test: I copied /etc/rc.conf (1062
bytes) to /tmp/test (& chmod u+w), then:

freebeast(16.0-C)[1] foreach i (`jot 10`)
foreach? ls -lT test && scp test albert:/tmp && cp test{,1} && cp test{,2} && cat test{1,2} >test
foreach? end
-rw-r--r--  1 david wheel 1062 Jul  8 04:59:42 2026 test
test                                          100% 1062     2.7MB/s   00:00
-rw-r--r--  1 david wheel 2124 Jul  8 05:02:44 2026 test
test                                          100% 2124     2.5MB/s   00:00
-rw-r--r--  1 david wheel 4248 Jul  8 05:02:45 2026 test
test                                          100% 4248     3.8MB/s   00:00
-rw-r--r--  1 david wheel 8496 Jul  8 05:02:45 2026 test
test                                          100% 8496     8.3MB/s   00:00
-rw-r--r--  1 david wheel 16992 Jul  8 05:02:45 2026 test
test                                          100%   17KB  20.4MB/s   00:00
-rw-r--r--  1 david wheel 33984 Jul  8 05:02:46 2026 test
test                                          100%   33KB  30.5MB/s   00:00
-rw-r--r--  1 david wheel 67968 Jul  8 05:02:46 2026 test
test                                            0%    0     0.0KB/s - stalled -

Then I tried again, making "test" smaller (by stripping the full-line
comments), so it started at 667 bytes.  It got as far as the 21344-byte
copy OK, but stalled on 42688.

OK, so then I had the notion to use ktrace to see where it was hanging:

freebeast(16.0-C)[44] ls -lT test*
-rw-r--r--  1 david wheel 42688 Jul  8 05:09:45 2026 test
-rw-r--r--  1 david wheel 21344 Jul  8 05:09:45 2026 test1
-rw-r--r--  1 david wheel 21344 Jul  8 05:09:45 2026 test2
freebeast(16.0-C)[45] ktrace -di scp test albert:/tmp
test                                          100%   42KB  24.5MB/s   00:00
freebeast(16.0-C)[46] scp test albert:/tmp
test                                            0%    0     0.0KB/s   --:-- ETA^Cfreebeast(16.0-C)[47]

Right: so it *works* under ktrace.  Of course.  OK; I think I'm out of
my depth here: anyone have a clue to offer?

Thanks....

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

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