From nobody Thu Apr 2 20:18:22 2026 Received: from out-180.mta1.migadu.com (out-180.mta1.migadu.com [95.215.58.180]) (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 B6ACA2D028A for ; Thu, 12 Feb 2026 08:23:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.180 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770884634; cv=none; b=g8PlgcQM0OaFzTkfnU7v00qSOyVK65P95ypxVBuKMJ29PevQhFKkkQZq9525tfQcJjGuQTal+w30gSr9WpkDS0cfuNYgpRvTkXqUrrVd8dsMpWsH6mFoTWbOimk+IcHNJmu1N6XAc8xfc/6WcqufBN/dapeUCvDta+vOAs19nqI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770884634; c=relaxed/simple; bh=9oiwq5b/PMLGO5TFSs8W4xMUf5GGnvMwLUvLVmePqIg=; h=From:To:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mrqtKO0Gu3Wmv4MS8XZYmhl1rDBH2rBZUix+ZNxx4yMzQu10LqELO4ijyozSMxL1axEAJRIRo8ocUfGnHFckTF6xM6Mudww4yNO/Nxv14dOEMjJqPcYOcWVRGVi7fDacgrB2MGgxjTsGvKCKV8nRqI4jQ8yPcXHRsjHxuX4Zaww= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=TDKuVggx; arc=none smtp.client-ip=95.215.58.180 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="TDKuVggx" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1770884630; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=crYbU+ThqI1KboSIh+EReNJtidB4zxhxhtyNUFlO0rY=; b=TDKuVggxscYGSctBSiDWdBR38fcvT+Z3PytbqBFCVFWT9qlg6PqmrB3xUNFaLH/XhUnQ0V /cNlB+mkcXUIsmjYfm600iLmjAGnPJAZe3pq7FPg8OY0WRq6FSaPe0IjxmUObaf1pjtqLO L5j2gXzjnb1A/e/bJWzIh5DBJ9GmIzg= From: Hui Zhu To: Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , Andrew Morton , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Shuah Khan , Hui Zhu , JP Kobryn , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH bpf-next 1/3] selftests/bpf: Check bpf_mem_cgroup_page_state return value Date: Thu, 12 Feb 2026 16:23:14 +0800 Message-ID: <042df9438d9e78bcd66f1fa0e7043b9ea8cda96c.1770883926.git.zhuhui@kylinos.cn> In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Content-Type: text/plain; charset="utf-8" From: Hui Zhu When back-porting test_progs to different kernel versions, I encountered an issue where the test_cgroup_iter_memcg test would falsely pass even when bpf_mem_cgroup_page_state() failed. The problem occurs when test_progs compiled on one kernel version is executed on another kernel with different enum values for memory statistics (e.g., NR_ANON_MAPPED, NR_FILE_PAGES). In such cases, bpf_mem_cgroup_page_state() returns -1 to indicate failure, but the test didn't check for this error condition and incorrectly reported success. This patch adds explicit checks to ensure bpf_mem_cgroup_page_state() doesn't return -1 before validating the actual statistics values. This prevents false positives when running test_progs in cross-kernel environments. Signed-off-by: Hui Zhu --- .../selftests/bpf/prog_tests/cgroup_iter_memcg.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_iter_memcg.c b/t= ools/testing/selftests/bpf/prog_tests/cgroup_iter_memcg.c index a5afd16705f0..13b299512429 100644 --- a/tools/testing/selftests/bpf/prog_tests/cgroup_iter_memcg.c +++ b/tools/testing/selftests/bpf/prog_tests/cgroup_iter_memcg.c @@ -53,6 +53,8 @@ static void test_anon(struct bpf_link *link, struct memcg= _query *memcg_query) if (!ASSERT_OK(read_stats(link), "read stats")) goto cleanup; =20 + ASSERT_NEQ(memcg_query->nr_anon_mapped, (unsigned long)-1, + "bpf_mem_cgroup_page_state NR_ANON_MAPPED"); ASSERT_GT(memcg_query->nr_anon_mapped, 0, "final anon mapped val"); =20 cleanup: @@ -88,6 +90,10 @@ static void test_file(struct bpf_link *link, struct memc= g_query *memcg_query) if (!ASSERT_OK(read_stats(link), "read stats")) goto cleanup_map; =20 + ASSERT_NEQ(memcg_query->nr_file_pages, (unsigned long)-1, + "bpf_mem_cgroup_page_state NR_FILE_PAGES"); + ASSERT_NEQ(memcg_query->nr_file_mapped, (unsigned long)-1, + "bpf_mem_cgroup_page_state NR_FILE_MAPPED"); ASSERT_GT(memcg_query->nr_file_pages, 0, "final file value"); ASSERT_GT(memcg_query->nr_file_mapped, 0, "final file mapped value"); =20 @@ -119,6 +125,8 @@ static void test_shmem(struct bpf_link *link, struct me= mcg_query *memcg_query) if (!ASSERT_OK(read_stats(link), "read stats")) goto cleanup; =20 + ASSERT_NEQ(memcg_query->nr_shmem, (unsigned long)-1, + "bpf_mem_cgroup_page_state NR_SHMEM"); ASSERT_GT(memcg_query->nr_shmem, 0, "final shmem value"); =20 cleanup: @@ -143,6 +151,8 @@ static void test_kmem(struct bpf_link *link, struct mem= cg_query *memcg_query) if (!ASSERT_OK(read_stats(link), "read stats")) goto cleanup; =20 + ASSERT_NEQ(memcg_query->memcg_kmem, (unsigned long)-1, + "bpf_mem_cgroup_page_state MEMCG_KMEM"); ASSERT_GT(memcg_query->memcg_kmem, 0, "kmem value"); =20 cleanup: @@ -170,6 +180,8 @@ static void test_pgfault(struct bpf_link *link, struct = memcg_query *memcg_query) if (!ASSERT_OK(read_stats(link), "read stats")) goto cleanup; =20 + ASSERT_NEQ(memcg_query->pgfault, (unsigned long)-1, + "bpf_mem_cgroup_page_state PGFAULT"); ASSERT_GT(memcg_query->pgfault, 0, "final pgfault val"); =20 cleanup: --=20 2.43.0