Re: Recent tpm_tis IRQ handling changes are causing kernel backtraces

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

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