Re: Linux 6.18

[Guenter Roeck]

Hi Brian,

On 12/1/25 20:50, Brian Norris wrote:
> On Mon, Dec 01, 2025 at 06:39:49PM -0800, Guenter Roeck wrote:
> > On Sun, Nov 30, 2025 at 03:59:17PM -0800, Linus Torvalds wrote:
> > ...
> > > Anyway, *today* the important kernel is the newly minted 6.18 release.
> > > Please do keep testing,
> >
> > Build results:
> > 	total: 158 pass: 158 fail: 0
> > Qemu test results:
> > 	total: 610 pass: 610 fail: 0
> > Unit test results:
> > 	pass: 666778 fail: 113
> >
> > In terms of testing, that is worse that it sounds. I enabled
> > CONFIG_PM_RUNTIME_KUNIT_TEST last week, and it results in widespread
> > test failures. Picking one (from x86_64):
> >
> > [   34.559694]     # pm_runtime_error_test: EXPECTATION FAILED at drivers/base/power/runtime-test.c:177
> > [   34.559694]     Expected 1 == pm_runtime_barrier(dev), but
> > [   34.559694]         pm_runtime_barrier(dev) == 0 (0x0)
> > [   34.563604]     # pm_runtime_error_test: pass:0 fail:1 skip:0 total:1
> >
> > Looks like that fails pretty much on every architecture/platform where
> > it is enabled. Copying the author (Brian) for feedback.
>
> I wonder how you manage to be the one who hits all these problems,
> because none of the configurations and environments generated by
> ./tools/testing/kunit/kunit.py seem to hit it naturally. (I tested
> hundreds of cycles in various configurations with no failures
> previously, and I still didn't reproduce it today.) Do you make special
> effort to direct cosmic rays into your test setups while holding an
> unlucky charm? :)

Neither cosmic rays nor unlucky charm needed (or at least so I hope ;-).

I build the tests into the kernel and run them while booting in qemu.
Most other testbeds run the tests as module after booting and/or
on native machines (not in qemu). That makes a significant difference
in both behavior and timing.

Guenter