Re: [BUG] More issues with arm/aes-neonbs

["Russell King (Oracle)" <linux@armlinux.org.uk>]

On Fri, Aug 09, 2024 at 12:40:39PM +0800, Herbert Xu wrote:
> On Thu, Aug 08, 2024 at 12:54:10PM -0700, Linus Torvalds wrote:
> >
> > I don't know the crypto registration API enough to even guess at what
> > the fix to break the recursion is.
> > 
> > Herbert?
> 
> Yes my plan is to fix this in the Crypto API and not do any recursive
> loads as we used to do.
> 
> The immediate cause of the recursive load is the self-test system
> (if it is not disabled through Kconfig).  The algorithm registration
> does not return until after the self-test has successfully executed.
> For the algorithm in question, that involves loading a fallback
> algorithm which is what triggered the recursive module load.
> 
> We had an issue when algorithms were built into the kernel, where
> due to the random of registration calls, a self-test may invoke
> an algorithm which is built into the kernel but not yet registered.
> There it was resolved by postponing all self-tests until all
> algorithms had been registered (or when an algorithm was first used,
> which would trigger the self-test for that algorithm there and then).
> 
> I will extend this to modules and let the registration return
> as soon as the new algorithm can be looked up.  The self-test
> can then complete asynchronously.
> 
> Russell, is it OK with you if we only resolve this in the mainline
> kernel or do you want a solution that can be backported as well?

That's fine - I've blacklisted the arm-aes-bs module in modprobe.conf
on the affected machines. Thanks!

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