[BUG] dm-crypt broken after 2632e2521769 ("arm64: fpsimd: Implement lazy restore for kernel mode FPSIMD")

[Ard Biesheuvel]

On Tue, 21 May 2024 at 20:44, Mark Brown <broonie at kernel.org> wrote:
>
> On Tue, May 21, 2024 at 07:34:45PM +0100, Will Deacon wrote:
>
> > I've already reverted 2632e2521769 ("arm64: fpsimd: Implement lazy
> > restore for kernel mode FPSIMD"), so it sounds like I should revert
> > aefbab8e77eb ("arm64: fpsimd: Preserve/restore kernel mode NEON at
> > context switch") as well while we work to reproduce the issue.
>
> For paranoia I'd be tempted to revert 9b19700e623f9 ("arm64: fpsimd:
> Drop unneeded 'busy' flag") as well since we're not sure where exactly
> the issue is, that'd drop the entire series.  It's hopefully excessive
> but the exact bisection doesn't seem 100% clear and obviously we missed
> something.

We'll need to revert this ccm change as well, but I'll need to do that manually.

88c6d50f649b2805bbdfe0b616892f93db47e4fa

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=88c6d50f649b2805bbdfe0b616892f93db47e4fa