Re: hmm_test issues with latest mainline

[Shuah Khan <skhan@linuxfoundation.org>]

On 10/13/22 10:54, Vlastimil Babka wrote:
> Hi,
> 
> I've been trying the hmm_tests as of today's commit:
> 
> a185a0995518 ("Merge tag 'linux-kselftest-kunit-6.1-rc1-2' ...)
> 
> and run into several issues that seemed worth reporting.
> 
> First, it seems the FIXTURE_TEARDOWN(hmm) in
> tools/testing/selftests/vm/hmm-tests.c
> using ASSERT_EQ(ret, 0); can run into an infinite loop of reporting the
> assertion failure. Dunno if it's a kselftests issue or it's a bug to
> use asserts in teardown. I hacked it up like this locally to proceed:
> 

kselftest pull requests didn't include any framework changes. I doubt
that it is framework related.

> --- a/tools/testing/selftests/vm/hmm-tests.c
> +++ b/tools/testing/selftests/vm/hmm-tests.c
> @@ -154,6 +154,11 @@ FIXTURE_TEARDOWN(hmm)
>   {
>   	int ret = close(self->fd);
>   
> +	if (ret != 0) {
> +		fprintf(stderr, "close returned (%d) fd is (%d)\n", ret,self->fd);
> +		exit(1);
> +	}
> +
>   	ASSERT_EQ(ret, 0);
>   	self->fd = -1;
>   }
> 
> Next, there are some tests that fail (and thus also trigger the issue above)
> 
> #  RUN           hmm.hmm_device_private.exclusive ...
> # hmm-tests.c:1702:exclusive:Expected ret (-16) == 0 (0)
> close returned (-1) fd is (3)
> # exclusive: Test failed at step #1
> #          FAIL  hmm.hmm_device_private.exclusive
> not ok 20 hmm.hmm_device_private.exclusive
> #  RUN           hmm.hmm_device_private.exclusive_mprotect ...
> # hmm-tests.c:1756:exclusive_mprotect:Expected ret (-16) == 0 (0)
> close returned (-1) fd is (3)
> # exclusive_mprotect: Test failed at step #1
> #          FAIL  hmm.hmm_device_private.exclusive_mprotect
> not ok 21 hmm.hmm_device_private.exclusive_mprotect
> #  RUN           hmm.hmm_device_private.exclusive_cow ...
> # hmm-tests.c:1809:exclusive_cow:Expected ret (-16) == 0 (0)
> close returned (-1) fd is (3)
> # exclusive_cow: Test failed at step #1
> #          FAIL  hmm.hmm_device_private.exclusive_cow
> not ok 22 hmm.hmm_device_private.exclusive_cow
> 
> I'll try to check more closely but maybe if you can reproduce it too, you'll
> have more idea what's going on.
> 

Sounds good.

> The next thing is more of a question/documentation suggestion. Tons of tests
> fail like this:
> 
> ok 24 hmm.hmm_device_private.hmm_cow_in_device
> #  RUN           hmm.hmm_device_coherent.open_close ...
> could not open hmm dmirror driver (/dev/hmm_dmirror2)
> #      SKIP      DEVICE_COHERENT not available
> #            OK  hmm.hmm_device_coherent.open_close
> 
> I assume this is because I run "test_hmm.sh smoke" without the SPM parameters.
> The help message doesn't say much about what to specify there for
> <spm_addr_dev0> <spm_addr_dev1>. Do these tests need a particular hardware?
> (unlike the rest?) Maybe it could be clarified.
> 
> Last thing, I noticed all these DEVICE_COHERENT tests ultimately count as OK,
> not SKIPPED, which would probably be more appropriate?
> 

Anytime a test can't be run due to missing config, the result should be a SKIP.
If that is not the case let's fix these cases.

> # FAILED: 51 / 54 tests passed.
> # Totals: pass:50 fail:3 xfail:0 xpass:0 skip:1 error:0
> 
> (the skip:1 is due to test 9 "#      SKIP      Huge page could not be allocated"
> which is probably a misconfiguration on my part so I don't report that as an issue)
> 

Skip is the right result in this case if it is indeed the result of misconfig.

thanks,
-- Shuah