Re: [regression] significant delays when secureboot is enabled since 6.10

[Jarkko Sakkinen]

On Tue Sep 10, 2024 at 12:05 PM EEST, Roberto Sassu wrote:
> On Tue, 2024-09-10 at 11:01 +0200, Linux regression tracking (Thorsten
> Leemhuis) wrote:
> > Hi, Thorsten here, the Linux kernel's regression tracker.
> > 
> > James, Jarkoo, I noticed a report about a regression in
> > bugzilla.kernel.org that appears to be caused by this change of yours:
> > 
> > 6519fea6fd372b ("tpm: add hmac checks to tpm2_pcr_extend()") [v6.10-rc1]
> > 
> > As many (most?) kernel developers don't keep an eye on the bug tracker,
> > I decided to forward it by mail. To quote from
> > https://bugzilla.kernel.org/show_bug.cgi?id=219229 :
> > 
> > > When secureboot is enabled,
> > > the kernel boot time is ~20 seconds after 6.10 kernel.
> > > it's ~7 seconds on 6.8 kernel version.
> > > 
> > > When secureboot is disabled,
> > > the boot time is ~7 seconds too.
> > > 
> > > Reproduced on both AMD and Intel platform on ThinkPad X1 and T14.
> > > 
> > > It probably caused autologin failure and micmute led not loaded on AMD platform.
> > 
> > It was later bisected to the change mentioned above. See the ticket for
> > more details.
>
> Hi
>
> I suspect I encountered the same problem:
>
> https://lore.kernel.org/linux-integrity/b8a7b3566e6014ba102ab98e10ede0d574d8930e.camel@xxxxxxxxxxxxxxx/
>
> Going to provide more info there.

I suppose you are going try to acquire the tracing data I asked?
That would be awesome, thanks for taking the troube.  Let's look
at the data and draw conclusions based on that.

Workaround is pretty simple: CONFIG_TCG_TPM2_HMAC=n to the kernel
configuration disables the feature.

For making decisions what to do with the  we are talking about ~2
week window estimated, given the Vienna conference slows things
down, so I hope my workaround is good enough before that.

> Roberto

BR, Jarkko