Re: Recent tpm_tis IRQ handling changes are causing kernel backtraces

[Jarkko Sakkinen <jarkko@kernel.org>]

On Tue, Jun 15, 2021 at 03:59:06PM +0200, Hans de Goede wrote:
> Hi,
> 
> On 6/15/21 3:01 PM, Jarkko Sakkinen wrote:
> > On Mon, Jun 14, 2021 at 03:33:33PM +0200, Hans de Goede wrote:
> >> Hi,
> >>
> >> On 6/1/21 6:04 PM, Hans de Goede wrote:
> >>> Hi,
> >>>
> >>> On 5/31/21 6:36 AM, Jarkko Sakkinen wrote:
> >>>>> Interestingly enough the first backtrace is also happening on a:
> >>>>> "Dell Inc. XPS 13 9310/0MRT12, BIOS 2.2.0 04/06/2021"
> >>>>>
> >>>>> So it seems that at least with 5.12.6 (which has the last 2 fixes)
> >>>>> all reports are about the XPS 13 9310. I wonder if there is an
> >>>>> issue with the TPM interrupt line on the XPS 13 9310; I've asked the
> >>>>> reporters to try adding tpm_tis.interrupts=0 to their kernel commandline.
> >>>>
> >>>> This is helpful for sure that these all are happening on matching hardware.
> >>>
> >>> So our kernel-backtrace tracking info (ABRT) just recorded a third backtrace
> >>> with a kernel >= 5.12.6, again on the XPS 13 9310, so now we have 3 variants:
> >>>
> >>> 1. Backtrace starting with a call to ima_add_boot_aggregate
> >>> https://bugzilla.redhat.com/show_bug.cgi?id=1963712
> >>>
> >>> 2. Backtrace starting with a call to tpm_dev_async_work:
> >>> https://bugzilla.redhat.com/show_bug.cgi?id=1964974
> >>> (note this one is not easily reproducible)
> >>>
> >>> 3. Backtrace starting with a call to rng_dev_read:
> >>> https://bugzilla.redhat.com/show_bug.cgi?id=1920510
> >>>
> >>> 3. is the new one. All bugs linked above are public, all 3 backtraces
> >>> so far have only been reported on the XPS 13 9310 (with kernel >= 5.12.6)
> >>> and I've asked all the reporters to check if tpm_tis.interrupts=0 helps.
> >>
> >> Quick status update, I've got a response from a XPS 13 9310 user in:
> >>
> >> https://bugzilla.redhat.com/show_bug.cgi?id=1920510
> >>
> >> Indicating that a. he can reproduce this with the latest >= 5.12.6 kernels;
> >> and b. it goes away when specifying tpm_tis.interrupts=0 as I expected
> >> (I expected this because all the bug-reports started when the interrupt
> >> code got fixed/re-enabled a while ago).
> >>
> >> Si I think that there just is something broken wrt the interrupt setup
> >> on the XPS 13 9310 and that we should probably add an antry for the
> >> XPS 13 9310 to the already existing tpm_tis_dmi_table pointing to the
> >> also already existing tpm_tis_disable_irq callback.
> >>
> >> If other people agree that that is probably the best way forward ?
> >> then I can prepare a patch and ask the user to test this.
> >>
> >> Regards,
> >>
> >> Hans
> > 
> > I think it all roots down to the use of TPM before tpm2_probe(), i.e.
> > TPM is not in expected state when tpm_chip_start() is called. I
> > suggested to try out adding tpm_chip_stop() right before
> > tpm_chip_start() in another response.
> > 
> > That's only thing that makes logically sense to me at least.
> 
> Shouldn't there the be some completion somewhere with get completed
> at the end of probe(), with the read-path which is involved in this
> case blocking on this?
> 
> If you can prepare a kernel-patch to test, then I can build a Fedora
> kernel rpm with the patch added for the user to test.
> 
> Regards,
> 
> Hans

After rc1 PR I'll have to check through the hardware that I have if
something would reproduce the issue locally. This is too blind shooting
ATM.

/Jarkko