Re: CVE-2024-46839: workqueue: Improve scalability of workqueue watchdog touch

[Greg Kroah-Hartman]

On Tue, Oct 01, 2024 at 10:02:02AM +0200, Petr Mladek wrote:
> On Fri 2024-09-27 14:40:07, Greg Kroah-Hartman wrote:
> > Description
> > ===========
> > 
> > In the Linux kernel, the following vulnerability has been resolved:
> > 
> > workqueue: Improve scalability of workqueue watchdog touch
> > 
> > On a ~2000 CPU powerpc system, hard lockups have been observed in the
> > workqueue code when stop_machine runs (in this case due to CPU hotplug).
> 
> I believe that this does not qualify as a security vulnerability.
> Any hotplug is a privileged operation.

Really?  I see that happen on many embedded systems all the time, they
add/remove CPUs while the device runs/sleeps constantly.

Now to be fair, right now an "embedded system" usually doesn't have 2000
cpus, but what's wrong with marking this real bugfix as a vulnerability
resolution?  If you don't run your system in a way that allows cpus to
be stopped unless an admin says so, it will not be relevant.

thanks,

greg k-h