Thanks to everyone who replied with suggestions. I tried or has already tried a number of them, including much of Greg Wooledge's nicely detailed recommendation and Michael's below (although not neatly packaged into a pipeline). None was fully successful.
In wandering through the various zfs snapshots and incarnations of /lib, /usr/lib, /lib64 and /usr/lib64 during attempts to apply a fix, I found that the original upgrade from Debian 11 to 12 appears to have been from 11.7, not 11.11. I suspect that, possibly combined with ongoing modifications associated with usrmerge, might have set up the environment to cause the update to 12.11 to fail. Accordingly, I am going to roll back to the file systems of Debian 11.7, reinstall grub, and try updating and upgrading normally from that point. I expect that to succeed. Again, thanks for the suggestions offered. Tom Dial On 7/21/25 01:16, Michael Paoli wrote:
Proceeded to seriously break system using rm on libc6:amd64 files. rmed (or attempted): all files of type ordinary file in libc6:amd64 package (per dpkg -L) plus symbolic links resolving to such, and putting as very last in that sequence, from information from ldd rm the overlapping files between the two and ordering within that last bit, first file(s) of type symbolic link resolving to files of type ordinary file, then files of type ordinary file. And yes, that of course seriously broke the system. :-) And from a "recovery" environment (actually physical host of the VM in this case, but regardless), use ar, xz, and tar to restore the files from the package (and avoiding the chroot complications of too much missing under target directory for most things to function under a chroot there).: With the target filesystem(s) mounted rw under mnt # ar p \ /var/cache/apt/archives/libc6_2.36-9+deb12u10_amd64.deb data.tar.xz | xz -d | (umask 022 && cd mnt && tar -xf -) Then unmounted, booted that (VM) host, and for good measure did: # apt-get install --reinstall libc6:amd64 Most notably so that would also cover running and pre/post scripts that might be needed, and also getting the package state appropriately set to cleanly installed in the APT database. All seems fine after that. On Sun, Jul 20, 2025 at 10:12 PM Michael Paoli <michael.pa...@berkeley.edu> wrote:
(Material omitted for brevity)
a) roll back to the initial install (Bullseye) and update/upgrade from that; or b) clear the disk and reinstall everything
