From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-181.mta1.migadu.com (out-181.mta1.migadu.com [95.215.58.181]) (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 EB8D0280A5B for ; Mon, 2 Mar 2026 18:27:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772476044; cv=none; b=k1LQck+cONzneAgZXTH4UjMiFiSfI2fZn5Uu/cbjCGZ29TS5269uTNCt1BD3IHSsMv3IM1BkRnBUlgA0fwPrmQD/KGGAXEeR/srnaJKsvn1fzEoTzCju0rMwFyzMKk6SYMz/dx/CAGLr7fDjR6pFvx6Yf5bca9UY4K4MFyclM1o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772476044; c=relaxed/simple; bh=BdFJzu5emJv9dTvAWLyKOoNL81Cc1hzE3KwrVS0bq4U=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ou1Fbix+Y5TDVvV2u0fiycE2WQXdsHRMJEjkmWUwkRLgZw36tlt7nwtMqxsTNqCyy18R32MHp1U3sq5ihpUPo4FeILzfYHwpX6joolxQfao3FQ2Qges68YmcP7QY/0C15N+O0CRCXmRcCl3Ap7RkX6sar391sXes2Y68aXzUP5A= 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=SP9WaUib; arc=none smtp.client-ip=95.215.58.181 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="SP9WaUib" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1772476040; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=QZP30HVE2qfuNyrPBqZl8V1Ig0caHRkDPE55WWDj3+I=; b=SP9WaUibvCr02TxS/rYaqUAmYtel7Bg8K7GueawK5vazwc4m1yW8Ze5VyqiugKUyPoc8va GXjKmpgwlKdu3hSBm0VJwHz3SQcg92WAfI20+Jl8lbH8y3mTeKlVwQOy7hX6LSiU8wPsyB YiYhftgYUVb7bfpni3BucHxc9cnF7mQ= Date: Mon, 2 Mar 2026 10:27:09 -0800 Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH bpf-next v4 3/3] selftests/bpf: Check bpf_mem_cgroup_page_state return value To: Hui Zhu , 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 , Roman Gushchin , bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Hui Zhu References: Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: "JP Kobryn (Meta)" In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 2/28/26 1:25 AM, Hui Zhu wrote: > 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. > > This patch adds explicit checks to ensure bpf_mem_cgroup_page_state() > doesn't return -1 before validating the actual statistics values. > > Signed-off-by: Hui Zhu > --- > .../selftests/bpf/prog_tests/cgroup_iter_memcg.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_iter_memcg.c b/tools/testing/selftests/bpf/prog_tests/cgroup_iter_memcg.c > index 88fc3e83d2b7..9eadfbd3fdb9 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; > > + 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"); > > cleanup: > @@ -88,6 +90,10 @@ static void test_file(struct bpf_link *link, struct memcg_query *memcg_query) > if (!ASSERT_OK(read_stats(link), "read stats")) > goto cleanup_map; > > + 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"); > > @@ -119,6 +125,8 @@ static void test_shmem(struct bpf_link *link, struct memcg_query *memcg_query) > if (!ASSERT_OK(read_stats(link), "read stats")) > goto cleanup; > > + 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"); > > cleanup: > @@ -144,6 +152,8 @@ static void test_pgfault(struct bpf_link *link, struct memcg_query *memcg_query) > if (!ASSERT_OK(read_stats(link), "read stats")) > goto cleanup; > > + ASSERT_NEQ(memcg_query->pgfault, (unsigned long)-1, > + "bpf_mem_cgroup_vm_events PGFAULT"); > ASSERT_GT(memcg_query->pgfault, 0, "final pgfault val"); > > cleanup: Emil mentioned in the v3 thread that we don't need these checks [0]. I agree. Now that you're using the bpf co-re enum helpers, the stat indexes won't become an issue in a cross-kernel secenario. This patch can be dropped. [0] https://lore.kernel.org/bpf/DGQXZVBSVEUP.35P5G9QOL9EAT@etsalapatis.com/T/#m7cb6edf90ed4daaeda38b746363317405f198f20