Comment 88 for bug 798414

I have found a problem several times running updates which are coming more and more often. That's probably good for security but the automated attempt to update adds a bunch of files to a root level directory, like this:

lenovo[~]> cd /boot
lenovo[/boot]> ls -l
total 92010
-rw-r--r-- 1 root root 1312266 Dec 2 15:52 abi-4.2.0-21-generic
-rw-r--r-- 1 root root 1312266 Dec 17 20:23 abi-4.2.0-22-generic
-rw-r--r-- 1 root root 184850 Dec 2 15:52 config-4.2.0-21-generic
-rw-r--r-- 1 root root 184850 Dec 17 20:23 config-4.2.0-22-generic
drw-rw-rw- 5 root root 1024 Dec 20 10:25 grub
-rw-r--r-- 1 root root 34594062 Dec 18 10:36 initrd.img-4.2.0-21-generic
-rw-r--r-- 1 root root 34597280 Dec 20 10:25 initrd.img-4.2.0-22-generic
drw-rw-rw- 2 root root 12288 May 26 2015 lost+found
-rw-r--r-- 1 root root 182704 Aug 27 09:04 memtest86+.bin
-rw-r--r-- 1 root root 184380 Aug 27 09:04 memtest86+.elf
-rw-r--r-- 1 root root 184840 Aug 27 09:04 memtest86+_multiboot.bin
-rw------- 1 root root 3740849 Dec 2 15:52 System.map-4.2.0-21-generic
-rw------- 1 root root 3740849 Dec 17 20:23 System.map-4.2.0-22-generic
-rw------- 1 root root 6799408 Dec 2 15:52 vmlinuz-4.2.0-21-generic
-rw------- 1 root root 6799856 Dec 17 20:23 vmlinuz-4.2.0-22-generic

To fix I have to login as root and delete older files that, hopefully, will never be needed for a backup.

There is plenty of extra room on the disk and it's hard to understand why the files can't just continue to waste space but I can't find evidence of some limit other than the disk itself. Is it possible that root has some limit to its own use?