13.4-RELEASE : freebsd-update fetch-then-install updated kernel but not /usr/lib/debug/boot/kernel/kernel.debug

I was looking have a context to be able to use kgdb for looking at
a 13.4-RELEASE-p2 (so: a 13.4-RELEASE-p1 kernel).

To get a set of files for 13.4-RELEASE-p2 I had to start from a
13.4-RELEASE and use freebsd-update : there is no direct download
of a kernel*.txz set or other such for the patched kernel, so far
as I can tell.

But the freebsd-update update-then-install sequence:

) Updated boot/kernel/kernel (and more)
yet:
) Did not update usr/lib/debug/boot/kernel/kernel.debug

After the update, kgdb reports for the updated context:

warning: the debug information found in "/usr/lib/debug//boot/kernel/kernel.debug" does not match "/boot/kernel/kernel" (CRC mismatch).

And I diff'd before-vs-after copies of
usr/lib/debug/boot/kernel/kernel.debug and it did not
have a change of content, nor did its modification
date change.

How is one supposed to investigate via, say, panic backtrace
addresses and such of a patched vintage of the likes of
13.4-RELEASE and its patched kernel? Does it require
setting up an environment for rebuilding from source that
will happen to accurately reproduce what the official
build produced?

I'd rather avoid the question of if a configuration for
(re-)building is the cause of a difference vs. other
potential causes of differences: I wish there were
known-good download files to use for reference.

I'll note that technically, for what I was attempting to
do, I should only need expanded kernel.txz , kernel-dbg.txz ,
and src.txz files if they were for the right patch level.
It is the need to use freebsd-update that leads to involving
far more.


Somewhat related Side note . . .

As noted in:

https://lists.freebsd.org/archives/freebsd-pkgbase/2024-December/000483.html

the likes of a PkgBase 14.2-RELEASE vs. a set of the *.txz for
the "same" 14.2-RELEASE are not a full match, apparently with:

) pad byte differences

) Differences in memory layout for .rodata through .eh_frame  .
   (File paths are recorded that have differing lengths, for
    example.)


===
Mark Millard
marklmi at yahoo.com