Re: Recent tpm_tis IRQ handling changes are causing kernel backtraces

[Jarkko Sakkinen <jarkko@kernel.org>]

On Mon, May 31, 2021 at 10:24:05AM +0200, Hans de Goede wrote:
> Hi,
> 
> On 5/31/21 6:36 AM, Jarkko Sakkinen wrote:
> > On Thu, May 27, 2021 at 05:27:49PM +0200, Hans de Goede wrote:
> >> This is from:
> >> https://retrace.fedoraproject.org/faf/reports/74723/  (public)
> > 
> > I wonder if this occurs only with O_NONBLOCK.
> > 
> > Any chances to get the output of
> > 
> >   sudo tools/testing/selftests/tpm2/test_smoke.sh
> > 
> > ?
> > 
> > It's obvious that there is some sort of bug, but it's not yet obvious that
> > this bug is connected to the locality issue yet, as in this case locality
> > is successfully reserved by tpm_try_get_ops() in tpm_dev_async_work()
> > (driver/chars/tpm/tpm-dev-common.c).
> 
> As mentioned I've asked the user to try with tpm_tis.interrupts=0 and see
> if that makes a difference. I got a reply that the user only hit this
> once and that this is not (easily) reproducible :|

This is not about interrupts. It's about opening the file with O_NONBLOCK.
I.e. the function returns and defers sending the command.

> "looks like a spurious problem that may already be solved."
> 
> I did get permission to open up the bug (make it public) so if you want
> more info it is probably easiest if you interact directly with the
> reporter here:
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=1964974
> 
> If you don't already have a bugzilla.redhat.com account, creating one
> is super easy, you only need to enter your email address and pick a
> password.

I'll create one. I don't actually remember if I have one or not :-)

/Jarkko