Re: [RFC PATCH bpf-next v3 2/2] selftests/livepatch: update test-ftrace.sh for deprecated ftrace_enabled
Miroslav Benes <[email protected]>
| Newsgroups | org.kernel.vger.bpf,org.kernel.vger.linux-trace-kernel,org.kernel.vger.live-patching,org.kernel.vger.stable |
|---|---|
| Message-ID | <[email protected]> |
> > We do not deprecate features. tracefs code is user API. We do not break > > user space. The ftrace_enabled is something that is being removed because > > it is broken to begin with. In fact, if we find out that anything depends > > on ftrace_enabled, we need to revert the change that disabled it. > > > > The removal of ftrace_enabled is the exception and not the rule. > > Agreed that ftrace APIs need to be very stable, as there are many out > of tree users. OTOH, I think livepatch can afford breaking some > compatibility. We discussed that a bit in the context of this patch set [1]. I think it is valuable to have the kselftests backward compatibility but there is of course some limit to it. We can talk about it at Plumbers during the backward compatibility session as well [2]. Miroslav [1] https://lore.kernel.org/all/[email protected]/ [2] https://lpc.events/event/20/contributions/2530/