David, I have to agree with Michal. If the user-space tool did what it
had to do for old kernels, then new kernels should support the old
semantics.

You can't call it a "bug" - user space does what it does and it was
tested and worked.

And sure, it might have been a bug/misfeature of the old kernel, but
we have to live with what we have done, not blame others. Once user
space starts depending on our bugs, it's *our* problem.

Saying "fix your sh*t" is wrong, when we caused it to begin with.

            Linus

On Thu, Jun 12, 2014 at 7:13 AM, Michal Schmidt [off-list ref] wrote:

On 06/03/2014 02:21 PM, Michal Schmidt wrote:

quoted

On 05/31/2014 02:42 AM, David Miller wrote:

quoted

The userspace tool should be fixed on the system, rather than having the
kernel cater to a user tool bug.

I'm not applying this, sorry.

the old version of the userspace tool did what it had to do in order to
work with a contemporary kernel. You can call that a bug, but the fact
is that it used to work that way.

I do not see a difference between "catering to a user tool bug" and
"not breaking applications, whether we like them or not" (paraphrasing
Linus's message on this very mailing list just 10 days ago).

Dave,
I am sorry for harping on this, but could you please either reconsider
the NAK, or explain what considerations are more important than
userspace compatibility in this case?

quoted

I could understand your objection if my proposed patch could break
something else, but you are not saying that, are you?

Michal