Re: [gentoo-user] Re: A helping hand with virtual machines, please.

[Michael Mol <mikemol@gmail.com>]

On Wed, Nov 23, 2011 at 10:09 AM, Alan McKinnon <alan.mckinnon@gmail.com> wrote:
> Lets grant that the VirtualBox modules are not up to LKML standards.
> That's fine, very little out of the tree is. I'm willing to bet that
> the majority of the issues are silly bugs involving pointer arithmetic
> (the usual cause of these things) and could be fixed up with minimal
> effort.
>
> Either way I don't think a sweeping condemnation of the entire product
> is the right way to go.

I read that entire thread back when it was highlighted on /.

1) The vbox driver is buggy.
2) The vbox driver is buggy in ways that cause crashes which are
difficult to debug and correctly attribute, which appears to be
discerned by statistical means.
3) The vbox driver upstream won't send their code to the kernel where
it could be cleaned up and kept in step with the rest of the kernel,
because it would restrict them from updating their API in future
versions.
4) The vbox driver functions as a wildcard when kernel devs are trying
to deal with bug reports in other areas of the code; just like heap
and stack corruption in userland apps are a royal PITA to deal with,
so are the same in kernelspace. The vbox driver is known to cause
these problems, so they don't want to deal with it.

Now, it looks like things may be in line to get better; the thread got
the attention of the vbox maintainers, and they started working on
ways to get flagged bug reports sent their way. That'll improve the
feedback they get. The code will probably improve as a result.

That said, drivers which cause random memory corruption are *not* ones
I want loaded into my kernel. Discussions around things like the vbox
kernel give me second thoughts about sweet dreams of mmapping
persistent storage block devices contiguously in a large address
space; I'd suddenly rather keep the window target small.

 I've got nothing against proprietary drivers if they're good. I've
generally had good luck with both NVidia and ATI, for example. NVidia,
especially, has been quick to respond to issues by their user
communities

> Oh, I forgot something in the first paragraph. In my experience on this
> machine we can add Firefox, OpenOffice.org and LibreOffice to the same
> list of unstable software.

Apples and oranges. FF, OO and LO don't crash the entire system when
they go up. Protected memory FTW.  Kernelspace stuff must be held to a
higher standard; they run in ring 0.

(Forgive the x86-specific terminology, but it should be analogous for
any protected-memory platform)

-- 
:wq