$ sudo cp -avi libattr.so.1.1.0 /lib/x86_64-linux-gnu/libattr.so.1.1.0
cp: error while loading shared libraries: /lib/x86_64-linux-gnu/libattr.so.1: unexpected PLT reloc type 0x00000107
Not many internet hits for PLT reloc type errors.
Managed to repair it with
$ sudo su -
# cat < libattr.so.1.1.0 > /lib/x86_64-linux-gnu/libattr.so.1.1.0
I had to use a network connection to my rpi to extract the file from the libattr deb downloaded from the Debian archive, and copy back over network, because tar invoked by dpkg wouldn't launch (same error, noticed it first from sed failing noisily on terminal launch, probably bash completions or something).
This happened shortly after testing linux-4.20~rc2 this evening, maybe it has a bug in its ext4 filesystem? I will report it, just in case.
turns out I am not the only one, the discussion on the bug report has triggered over 100 emails with no resolution yet
https://bugzilla.kernel.org/show_bug.cgi?id=201685 ext4 file system corruption
Kernel developers on my bug report have made some progress, one was able to reproduce in QEMU, which makes bisecting much easier (I'm trying to reproduce their method now), moreover it seems likely to be something in the blk_mq layer below the ext4 filesystem. I don't know what that means, but it sounds bad. One candidate bad patch was introduced early in 4.19 release cycle.