Comment # 52 on bug 1112824 from Benjamin Sabatini

(In reply to Dead Mozay from comment #51)
> (In reply to Nicol�s Luciano B�rtolo from comment #50)
> > I tried kernel-vanilla and I found that it runs even better than
> > kernel-default with spectre mitigations off. Can anybody replicate my
> > findings?
> 
> in 4.19.4 a patch has already been adopted that disables stibp, by the way
> stibp was enabled in 4.14, but yes, performance improves with vanilla kernel

So problem not fixed in the default kernel. As many have said several times,
the problem was pre 4.19.2. In other words, it is not because of STIBP.