From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3EEEC235045; Thu, 9 Oct 2025 16:00:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760025646; cv=none; b=DGc6YQ7DutHDPGKxnLhJRpvm+ygAYYc/+M6T77y0RMdDw9zPhwBy31c94CSbVVtLDlF9tDlaRSP/b+Q0f7FYHqKea7sc8RNRYzuxo3UK8JFXtAD2l3YtqJaHvQ0eHSoxaHiNsyZjA5JDGLygnM2ust4rwKQGxLTMP05yylfBKz8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760025646; c=relaxed/simple; bh=3ddmq0SpXLemPFO6TxFKmdptKIsO1mwPG/RIEq8UZao=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=I75Kct7+IWzFpNym27fIwwk9UE1TGaUtwHff0gbgZ7JpVUcHhbEgY7s9Bf0d1teq4CitrY75n5FafYQoKWrHe+vhNxu59SHt64lceyJV8lV5mFRnkqtGT8qw9LT9kQJAc7dgUsq/v+1dEJNZsK9snPkMIflwIdgLmYGVXj8Ofsc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ENp15NjW; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ENp15NjW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B1954C4CEF7; Thu, 9 Oct 2025 16:00:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760025645; bh=3ddmq0SpXLemPFO6TxFKmdptKIsO1mwPG/RIEq8UZao=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ENp15NjWZ7c3r/ooTpZPWuysh+hJs9E5LY+4KDecmDTRISkEmDS9GFPv/SMFD9kZg J4ZxI23GW9yhQVB5jJwPPp692oWZ7InwoDv2NwyPCgjaTscyw2k3kWLD8wwrVnjKk8 7OdPY7ZwGwvLbD7U+URS7AlZFMn37Guh/1nhbBaC1iABRrAWkuC0eGcU1odgq9zVNg 6e05ex80CAIYjQCMhA8N6it/iB4aTX5qjB2Skyijgy4XSF9sSCeunSHaaf3OK6JwyG 7eeWGZ3ZugK21CJXYknXzVdcVO0vVBov3FXyM9dAjoWxhrj6g5ycCmakE85EczSf/e 62TJenjaLC3jw== From: Sasha Levin To: patches@lists.linux.dev, stable@vger.kernel.org Cc: Saket Kumar Bhaskar , Venkat Rao Bagalkote , Alexei Starovoitov , Sasha Levin , memxor@gmail.com, iii@linux.ibm.com, andrii@kernel.org, bpf@vger.kernel.org Subject: [PATCH AUTOSEL 6.17-6.16] selftests/bpf: Fix arena_spin_lock selftest failure Date: Thu, 9 Oct 2025 11:55:58 -0400 Message-ID: <20251009155752.773732-92-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251009155752.773732-1-sashal@kernel.org> References: <20251009155752.773732-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.17.1 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Saket Kumar Bhaskar [ Upstream commit a9d4e9f0e871352a48a82da11a50df7196fe567a ] For systems having CONFIG_NR_CPUS set to > 1024 in kernel config the selftest fails as arena_spin_lock_irqsave() returns EOPNOTSUPP. (eg - incase of powerpc default value for CONFIG_NR_CPUS is 8192) The selftest is skipped incase bpf program returns EOPNOTSUPP, with a descriptive message logged. Tested-by: Venkat Rao Bagalkote Signed-off-by: Saket Kumar Bhaskar Link: https://lore.kernel.org/r/20250913091337.1841916-1-skb99@linux.ibm.com Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- LLM Generated explanations, may be completely bogus: YES - `arena_spin_lock` returns `-EOPNOTSUPP` once `CONFIG_NR_CPUS` exceeds 1024 (`tools/testing/selftests/bpf/progs/bpf_arena_spin_lock.h:497`), so on platforms like powerpc (default 8192 CPUs) every test run exits early and the user space harness currently asserts that the retval must be zero (`tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c:41-47` before this change), causing the subtests to fail outright. - The patch teaches the harness to recognize that specific failure mode: `spin_lock_thread()` now short‑circuits when it sees `-EOPNOTSUPP` instead of tripping the ASSERT (`tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c:44-50`), and the BPF program annotates the condition by setting `test_skip = 3` before returning (`tools/testing/selftests/bpf/progs/arena_spin_lock.c:40-44`). - After all worker threads complete, the host test checks that flag, prints an explicit skip message, and marks the subtest as skipped instead of comparing the counter and failing (`tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c:94-101`). This lets kselftest succeed on high-NR_CPUS systems while still reporting the unsupported configuration. - The change is entirely confined to selftests, has no runtime or ABI impact, and aligns the tests with the documented hardware limitation, making it a low-risk fix for a real, reproducible failure on existing platforms. .../selftests/bpf/prog_tests/arena_spin_lock.c | 13 +++++++++++++ tools/testing/selftests/bpf/progs/arena_spin_lock.c | 5 ++++- 2 files changed, 17 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c b/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c index 0223fce4db2bc..693fd86fbde62 100644 --- a/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c +++ b/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c @@ -40,8 +40,13 @@ static void *spin_lock_thread(void *arg) err = bpf_prog_test_run_opts(prog_fd, &topts); ASSERT_OK(err, "test_run err"); + + if (topts.retval == -EOPNOTSUPP) + goto end; + ASSERT_EQ((int)topts.retval, 0, "test_run retval"); +end: pthread_exit(arg); } @@ -63,6 +68,7 @@ static void test_arena_spin_lock_size(int size) skel = arena_spin_lock__open_and_load(); if (!ASSERT_OK_PTR(skel, "arena_spin_lock__open_and_load")) return; + if (skel->data->test_skip == 2) { test__skip(); goto end; @@ -86,6 +92,13 @@ static void test_arena_spin_lock_size(int size) goto end_barrier; } + if (skel->data->test_skip == 3) { + printf("%s:SKIP: CONFIG_NR_CPUS exceed the maximum supported by arena spinlock\n", + __func__); + test__skip(); + goto end_barrier; + } + ASSERT_EQ(skel->bss->counter, repeat * nthreads, "check counter value"); end_barrier: diff --git a/tools/testing/selftests/bpf/progs/arena_spin_lock.c b/tools/testing/selftests/bpf/progs/arena_spin_lock.c index c4500c37f85e0..086b57a426cf5 100644 --- a/tools/testing/selftests/bpf/progs/arena_spin_lock.c +++ b/tools/testing/selftests/bpf/progs/arena_spin_lock.c @@ -37,8 +37,11 @@ int prog(void *ctx) #if defined(ENABLE_ATOMICS_TESTS) && defined(__BPF_FEATURE_ADDR_SPACE_CAST) unsigned long flags; - if ((ret = arena_spin_lock_irqsave(&lock, flags))) + if ((ret = arena_spin_lock_irqsave(&lock, flags))) { + if (ret == -EOPNOTSUPP) + test_skip = 3; return ret; + } if (counter != limit) counter++; bpf_repeat(cs_count); -- 2.51.0