> > In considering this, I realized htat we have a potentially serious problem > - if you install a new libc on an older-kernel system, it may well blow up > in a way that cannot easily be recovered. So I've written a mini-policy > > this is pretty much correct. in netbsd we basically say that if you > have a new kernel (with old "options" enabled) an old userland should > work fine, but new userland with old kernel is completely unsupported. > > covering a way to prevent this (in the absence of versioned Provides; we > can't just Provide: netbsd-kernel (1.6.1) in any form). One thing to be > careful of, and I'd like some refresher on this point, is whether the > COMPAT stuff in the kernel can provide old interfaces sufficiently well > that having, say, a -current kernel with COMPAT for 1.6.1 means you can > sanely use 1.6.1 libc or kernel-reading tools. > > it is a bug if a new kernel with (all) COMPAT options is not able to > run old software. perhaps the only exception to this is ld.elf_so, > but in general that also applies (there *are* exceptions though.)
I don't understand this - does this mean that all dynamically linked programs (i.e. almost all programs) will fail? > > [ .. ] > > NetBSD requires that the kernel and core libraries stay in fairly tight > sync; to this end, a special set of meta-packages are used for Provides (to > work around the fact that Provides can't be versioned, and the fact that a > given kernel can support older releases, but does not always do so). > > as i said above, it's a bug if a new kernel fails to run old userland. I remember our discussion about this some time ago. KVM-reading programs can fail, while sysctl-reading should not, is this right? What programs do depend on KVM? I guess among those are netstat and fstat. What about ps? Its man page mentions only using /dev/kmem , not sysctl. Bye Pavel
