Re: [PATCH v10 38/40] kselftest/arm64: Add a GCS stress test

From: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
To: Mark Brown <broonie@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
	 Will Deacon <will@kernel.org>,  Jonathan Corbet <corbet@lwn.net>,
	 Andrew Morton <akpm@linux-foundation.org>,
	 Marc Zyngier <maz@kernel.org>,
	 Oliver Upton <oliver.upton@linux.dev>,
	 James Morse <james.morse@arm.com>,
	 Suzuki K Poulose <suzuki.poulose@arm.com>,
	 Arnd Bergmann <arnd@arndb.de>,  Oleg Nesterov <oleg@redhat.com>,
	 Eric Biederman <ebiederm@xmission.com>,
	Shuah Khan <shuah@kernel.org>,
	 "Rick P. Edgecombe" <rick.p.edgecombe@intel.com>,
	 Deepak Gupta <debug@rivosinc.com>,
	 Ard Biesheuvel <ardb@kernel.org>,
	 Szabolcs Nagy <Szabolcs.Nagy@arm.com>,
	Kees Cook <kees@kernel.org>,  "H.J. Lu" <hjl.tools@gmail.com>,
	 Paul Walmsley <paul.walmsley@sifive.com>,
	 Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	 Florian Weimer <fweimer@redhat.com>,
	Christian Brauner <brauner@kernel.org>,
	 Ross Burton <ross.burton@arm.com>,
	 linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
	 kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org,
	 linux-arch@vger.kernel.org, linux-mm@kvack.org,
	 linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
	 linux-riscv@lists.infradead.org
Subject: Re: [PATCH v10 38/40] kselftest/arm64: Add a GCS stress test
Date: Wed, 07 Aug 2024 19:39:54 -0300	[thread overview]
Message-ID: <877ccsdkjp.fsf@linaro.org> (raw)
In-Reply-To: <20240801-arm64-gcs-v10-38-699e2bd2190b@kernel.org> (Mark Brown's message of "Thu, 01 Aug 2024 13:07:05 +0100")

Mark Brown <broonie@kernel.org> writes:

> Add a stress test which runs one more process than we have CPUs spinning
> through a very recursive function with frequent syscalls immediately prior
> to return and signals being injected every 100ms. The goal is to flag up
> any scheduling related issues, for example failure to ensure that barriers
> are inserted when moving a GCS using task to another CPU. The test runs for
> a configurable amount of time, defaulting to 10 seconds.
>
> Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
> Signed-off-by: Mark Brown <broonie@kernel.org>
> ---
>  tools/testing/selftests/arm64/gcs/.gitignore       |   2 +
>  tools/testing/selftests/arm64/gcs/Makefile         |   6 +-
>  tools/testing/selftests/arm64/gcs/asm-offsets.h    |   0
>  .../selftests/arm64/gcs/gcs-stress-thread.S        | 311 ++++++++++++
>  tools/testing/selftests/arm64/gcs/gcs-stress.c     | 530 +++++++++++++++++++++
>  5 files changed, 848 insertions(+), 1 deletion(-)

Unfortunately, gcs-stress still fails on my FVP setup. I tested on an
arm64 defconfig with and without THP enabled with, the same results:

$ sudo ./run_kselftest.sh -t arm64:gcs-stress -o 600
TAP version 13
1..1
# overriding timeout to 600
# selftests: arm64: gcs-stress
# TAP version 13
# 1..9
# # 8 CPUs, 9 GCS threads
# # Will run for 10s
# # Started Thread-4870
# # Started Thread-4871
# # Started Thread-4872
# # Started Thread-4873
# # Started Thread-4874
# # Started Thread-4875
# # Started Thread-4876
# # Started Thread-4877
# # Started Thread-4878
# # Waiting for 9 children
# # Waiting for 9 children
# # Thread-4870: Failed to enable GCS
# # Thread-4871: Failed to enable GCS
# # Thread-4872: Failed to enable GCS
# # Thread-4873: Failed to enable GCS
# # Thread-4876: Failed to enable GCS
# # Thread-4875: Failed to enable GCS
# # Thread-4874: Failed to enable GCS
# # Thread-4878: Failed to enable GCS
# # Thread-4877: Failed to enable GCS
# # Sending signals, timeout remaining: 10000ms
# # Sending signals, timeout remaining: 9900ms
# # Sending signals, timeout remaining: 9800ms
       ⋮
# # Sending signals, timeout remaining: 300ms
# # Sending signals, timeout remaining: 200ms
# # Sending signals, timeout remaining: 100ms
# # Finishing up...
# # Thread-4870 exited with error code 255
# not ok 1 Thread-4870
# # Thread-4871 exited with error code 255
# not ok 2 Thread-4871
# # Thread-4872 exited with error code 255
# not ok 3 Thread-4872
# # Thread-4873 exited with error code 255
# not ok 4 Thread-4873
# # Thread-4874 exited with error code 255
# not ok 5 Thread-4874
# # Thread-4875 exited with error code 255
# not ok 6 Thread-4875
# # Thread-4876 exited with error code 255
# not ok 7 Thread-4876
# # Thread-4877 exited with error code 255
# not ok 8 Thread-4877
# # Thread-4878 exited with error code 255
# not ok 9 Thread-4878
# # Totals: pass:0 fail:9 xfail:0 xpass:0 skip:0 error:0
ok 1 selftests: arm64: gcs-stress
bauermann@armv94:/var/tmp/selftests-arm64-gcs-v10$ echo $?
0

-- 
Thiago