userspace breakage

Dave Jones
2005-12-29T22:41:10Z

On Thu, Dec 29, 2005 at 12:49:16PM -0800, Linus Torvalds wrote:

> Umm.. Complain more. I upgrade kernels a lot more often than I upgrade
> distros, and things don't break. They're not allowed to break, because I
> refuse to upgrade my user programs just because I do kernel development.
> But I'd only notice a small part of user space, so if people don't
> complain, they break not because we don't care, but because we didn't even
> know.
>
> So if you have a user program that breaks, _complain_. It's really not
> supposed to happen outside of perhaps kernel module loaders etc things
> that get really really chummy with kernel internals (and even that was
> fixed: the modern way of loading modules isn't that chummy any more, so
> hopefully we'll not need to break even module loaders again).
>
> If we change some /proc file thing, breakage is often totally
> unintentional, and complaining is the right thing - people might not even
> have realized it broke.
>
> At least _I_ take breakage reports seriously. If there are maintainers
> that don't, complain to them. I'll back you up. Breaking user space simply
> isn't acceptable without years of preparation and warning.

The udev situation I mentioned has been known about for at least a month,
probably longer. With old udev, we don't get /dev/input/event* created
with 2.6.15rc.

At some point in time it became defacto that certain things like udev, hotplug,
alsa-lib, wireless-tools and a bunch of others have to have kept in lockstep
with the kernel, and if it breaks, it's your fault for not upgrading
your userspace.

Seriously, I (and many others) have been complaining about this
for months. (Pretty much every time the "Please can we have a 2.7"
thread comes up). [note, that I actually prefer the 'new' approach
to development in 2.6, what I object to is that at the same time we
threw out the 'lets be careful about not breaking userspace' mantra.]

Just a few years ago, if someone suggested breaking a userspace
app in a kernel upgrade, they'd be crucified on linux-kernel, now
it's 'the norm').

Dave