Re: Console/getty handling bug

Bernie Doehner (bad@ee.WPI.EDU)
Tue, 25 Jul 1995 11:31:37 -0500 (EDT)


> With kernel version 1.2.11 and beyond (I even tried 1.3.11), whenever NO
> gettys are running on the system, and one logs in via the ethernet network
> "init" ends up running all the time and grabs
> roughly 80-90% of system cpu time, even while the system is idle
> To make sure this wasn't related to something on my
> 386, I also disabled all gettys on my 486 and logged in via the network
> and noticed the same "init" behavior. This strange init behavior
> immediately goes away when I edit /etc/inittab, and kill -1 1 to start at
> least one getty.


I received some emails about this and it seems that I did not make my
point clear enough:

1. This problem does not occur with kernel 1.2.3 or before (does occur
with 1.2.11 and all the 1.3 kernels I tried).

2. The 486 that this was also tested on, has a fresh slackware 2.3
installation, so I doubt very much that there is anything wrong with the
init configuration on this machine.

3. Someone suggested that I shouldn't worry about one agetty running on
a 5MB system because it probably will get swapped out. This is fine if
the system has a hard drive. However I am working on setting up a 386
with 4MB of RAM, no monitor, no hard drive, and two floppy drives as a
ax25 router. This machine will only be going routing and will have
NO SWAP space, so it will be important that as few programs as possible
have to be running on it.

4. I don't quite know what to call this. If it really a bug. "Getty
handling bug" might be a better name, since it doesn't seem to have to
do much with the console.

If someone has a access to root on a networked Linux machine please try
this out yourself: Log in via the network, comment all getty's in
/etc/inittab, save the new inittab, kill -1 1 to stop all gettys, and
watch 'init'. After about 30 seconds it should start running and
depending on your cpu see anywhere between 50-90% CPU useage.

Please let us/me know what you find.


Bernie Doehner