On 20/03/18 18:00, David Miller wrote:
From: Liran Alon <liran.a...@oracle.com>
Date: Tue, 20 Mar 2018 17:34:38 +0200
I personally don't understand why we should maintain
backwards-comparability to this behaviour.
The reason is because not breaking things is a cornerstone of Linux
kernel development.
This feature is not documented to user-mode and I don't see why it
is legit for the user to rely on it.
Whether it is documented or not is irrelevant. A lot of our
interfaces and behaviors are not documented or poorly documented
at best.
In addition, even if we do want to maintain backwards-comparability to
this behaviour, I think it is enough to have an opt-in flag in
/proc/sys/net/core/ that when set to 1 will activate the fix in
dev_forward_skb() provided by this patch. That would also be a very
simple change to the patch provided here.
Making it opt-in makes it more palatable, that's for sure.
1. Do we want to make a flag for every bug that is user-space visible? I
think there is place for consideration on a per-case basis. I still
don't see how a user can utilize this behaviour. He is basically loosing
information (skb->mark) without this patch.
2. Having said that, I don't mind changing patch to maintain backwards
compatibility here. However, there was also a discussion here on where
the flag should sit. I think that a global /proc/sys/net/core/ flag
should be enough. Do you agree it's sufficient for now?
Thanks,
-Liran
