Re: [Ksummit-discuss] [topic proposal] tracepoints and ABI stability warranties

[Alexey Dobriyan <adobriyan@gmail.com>]

On Tue, Sep 06, 2016 at 03:22:43PM -0400, Steven Rostedt wrote:
> On Tue, 6 Sep 2016 19:51:43 +0100
> Al Viro <viro@ZenIV.linux.org.uk> wrote:
> 
> > 	I think this is something that needs to be discussed at KS; IMO we
> > need at least some way to express the degree of stability promises made
> > wrt individual tracepoints and some mechanisms for preventing silent creep
> > towards full stability; something along the lines of "unstable tracepoint $FOO
> > used by $PROGRAM, kernel tainted", at least.
> 
> What about having a set of tracepoints that are only enabled if one
> adds to the kernel command line "this-kernel-is-broken" and a big
> printk banner saying something like:

The solution was out there for quite some time :-)

	Scope of Compatibility
	Packages in Red Hat Enterprise Linux are classified under one of
	the following four compatibility levels:

	[ ] Compatibility level 1: APIs and ABIs are stable across three
	    major releases;

	[ ] Compatibility level 2: APIs and ABIs are stable within one major
	    release.

	[ ] Compatibility level 3: Reserved for future use.

	[X] Compatibility level 4: No compatibility is provided.

The winning move is to not play and let distros sort it out.

P.S.: techically every kernel release almost certainly breaks crash(1)
program, program many people on this list should be familiar with.
It is unclear why rules should be different for tracepoints.