Re: [patch 1/2] x86,module: Detect VMX modules and disable Split-Lock-Detect

[Steven Rostedt]

On Mon, 6 Apr 2020 17:22:31 +0200
Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> On Mon, Apr 06, 2020 at 08:18:47AM -0700, Christoph Hellwig wrote:
> > On Mon, Apr 06, 2020 at 04:40:20PM +0200, Peter Zijlstra wrote:  
> > > It is absolutely bonkers, but at the same time we can extend this
> > > infrastructure to scan for dubious code patterns we don't want to
> > > support. Like for instance direct manipulation of CR4.  
> > 
> > But that is not what this code does - it disables split lock detection.
> > If it failed to load the module the whole thing would make a little
> > more sense.  
> 
> If this lives, it'll be to just to fail module loading. IIRC the same
> was suggested elsewhere in the thread.

I believe I may have been the one to suggest it. It's no different than
breaking kabi if you ask me. If a module can't deal with a new feature,
than it should not be able to load. And let whoever owns that module fix it
for their users.

-- Steve