Re: [PATCH 6.6 000/122] 6.6.28-rc1 review

Greg Kroah-Hartman
2024-04-17T07:05:17Z

On Tue, Apr 16, 2024 at 06:28:10PM +0100, Catalin Marinas wrote:
> On Tue, Apr 16, 2024 at 02:22:07PM +0100, Marc Zyngier wrote:
> > On Tue, 16 Apr 2024 14:07:30 +0100,
> > Naresh Kamboju <naresh.kamboju@linaro.org> wrote:
> > > On Tue, 16 Apr 2024 at 16:04, Mark Brown <broonie@kernel.org> wrote:
> > > > On Mon, Apr 15, 2024 at 04:19:25PM +0200, Greg Kroah-Hartman wrote:
> > > > > This is the start of the stable review cycle for the 6.6.28 release.
> > > > > There are 122 patches in this series, all will be posted as a response
> > > > > to this one. If anyone has any issues with these being applied, please
> > > > > let me know.
> > > >
> > > > The bisect of the boot issue that's affecting the FVP in v6.6 (only)
> > > > landed on c9ad150ed8dd988 (arm64: tlb: Fix TLBI RANGE operand),
> > > > e3ba51ab24fdd in mainline, as being the first bad commit - it's also in
> > > > the -rc for v6.8 but that seems fine. I've done no investigation beyond
> > > > the bisect and looking at the commit log to pull out people to CC and
> > > > note that the fix was explicitly targeted at v6.6.
> > >
> > > Anders investigated this reported issues and bisected and also found
> > > the missing commit for stable-rc 6.6 is
> > > e2768b798a19 ("arm64/mm: Modify range-based tlbi to decrement scale")
> >
> > Which is definitely *not* stable candidate. We need to understand why
> > the invalidation goes south when the scale go up instead of down.
>
> If you backport e3ba51ab24fd ("arm64: tlb: Fix TLBI RANGE operand")
> which fixes 117940aa6e5f ("KVM: arm64: Define
> kvm_tlb_flush_vmid_range()") but without the newer e2768b798a19
> ("arm64/mm: Modify range-based tlbi to decrement scale"), it looks like
> "scale" in __flush_tlb_range_op() goes out of range to 4. Tested on my
> CBMC model, not on the actual kernel. It may be worth adding some
> WARN_ONs in __flush_tlb_range_op() if scale is outside the 0..3 range or
> num greater than 31.
>
> I haven't investigated properly (and I'm off tomorrow, back on Thu) but
> it's likely the original code was not very friendly to the maximum
> range, never tested. Anyway, if one figures out why it goes out of
> range, I think the solution is to also backport e2768b798a19 to stable.

How about I drop the offending commit from stable and let you all figure
out what needs to be added before applying anything else :)

thanks,

greg k-h