Re: [PATCH 6.1 00/42] 6.1.15-rc1 review

[Paolo Abeni]

On Fri, 2023-03-03 at 12:44 +0100, Greg Kroah-Hartman wrote:
> On Fri, Mar 03, 2023 at 12:39:07PM +0100, Paolo Abeni wrote:
> > Additionally, some self-tests check for known bugs/regressions. Running
> > them on older kernel will cause real trouble, and checking for bug
> > presence in the running kernel would be problematic at best, I think.
> 
> No, not at all, why wouldn't you want to test for know bugs and
> regressions and fail?  That's a great thing to do, and so you will know
> to backport those bugfixes to those older kernels if you have to use
> them.

I'm sorry, I likely was not clear at all. What I mean is that the self-
test for a bug may trigger e.g. memory corruption on the bugged kernel
(or more specifically to networking, the infamous, recurring
"unregister_netdevice: waiting for ...") which in turn could cause
random failures later.

If that specific case runs on older (unpatched) kernel will screw the
overall tests results. The same could happen in less-detectable way for
old bugs non explicitly checked by any test, but still triggered by the
test-suite. As a consequence I expect that the results observed running
newer self-tests on older kernel are unreliable. 

Cheers,

Paolo