Re: Recent tpm_tis IRQ handling changes are causing kernel backtraces]

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

Hi,

On 6/29/21 8:04 PM, Jarkko Sakkinen wrote:
> On Wed, Jun 23, 2021 at 03:54:59PM +0200, Hans de Goede wrote:
>> 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
> 
> Does "tpm_tis.interrupts=0" uniformly workaround the issue?

I unfortunately have not gotten much replies to my request to test with
tpm_tis.interrupts=0, but for those people who have bothered to test
(2 reporters IIRC) using tpm_tis.interrupts=0 does avoid the issue.

Regards,

Hans