On Thu, Aug 27, 2015 at 4:18 PM, David Miller [off-list ref] wrote:

From: Cong Wang <redacted>
Date: Thu, 27 Aug 2015 15:47:55 -0700

quoted

On Thu, Aug 27, 2015 at 3:42 PM, David Miller [off-list ref] wrote:

quoted

If you fix it properly, by making every qdisc capable of being ->init()'d
without explicit parameters, it will be the best behavior overall.

The problem is ->init() is not even called when setting it as default,
since setting a default qdisc doesn't need to create a qdisc. This is
why the flag has to be in ops->flags rather than qdisc->flags.

Just sounds like another shortcoming of how default qdiscs are handled,

It has to, due to its definition. I don't see any other way except we change
the meaning of the default qdisc.

rather than a reason to not fix things properly.

If you mean the crash, my patch can fix it too by simply rejecting the
invalid and buggy case like HTB, even though I do have local patches
to fix it directly.

Like I said, the more important question is not if it crashes, it is if we
should reject invalid case as early as possible or just wait for an error
to happen later.