Re: Recent tpm_tis IRQ handling changes are causing kernel backtraces

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 6/23/21 3:40 PM, Jarkko Sakkinen wrote:
> On Mon, Jun 21, 2021 at 02:04:52PM +0200, Hans de Goede wrote:
>> Hi,
>>
>> On 6/14/21 3:33 PM, 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).
>>
>> One more status update.
>>
>> - A new 4th variant of the backtrace has been spotted, where the problem hits
>> when called from probe() -> tpm2_auto_startup -> tpm2_do_selftest, see:
>> https://bugzilla.redhat.com/show_bug.cgi?id=1958381
>>
>> - So far all reports with kernel >= 5.12.6 have been on a Dell XPS 13 9310
>> models. But the new variant is happening on a Dell XPS 15 9500 and the
>> backtrace starting at ima_add_boot_aggregate is also being reported on
>> a Dell XPS 15 9500 (as well as on the XPS 13 9310).
>>
>> Regards,
>>
>> Hans
> 
> OK, I'll have to query if I could borrow that laptop from someone. It's
> fairly common laptop, i.e. might be possible.

In the mean time I've also got a report that this variant of the backtrace:

1. Backtrace starting with a call to ima_add_boot_aggregate
https://bugzilla.redhat.com/show_bug.cgi?id=1963712

Is also still happening with recent 5.12.y kernels on
Dell Precision 7750 laptops. Both the Precision 7750 and the XPS 9500 use
10th gen comet lake processors (i7-10750H), where as the XPS 9310 is using
an icelake processor. So the common denominator seems to be that they are
all 2020 Dell laptop models using the latest Intel CPUs.

FYI the complete list of models on which some of the 4 backtrace variants
are still seen on recent 5.12.y kernels is now:

Dell XPS 13 9310
Dell XPS 15 9500
Dell Precision 7750

Regards,

Hans