From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 672A5EDF055 for ; Thu, 12 Feb 2026 08:24:01 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C8F1F6B008A; Thu, 12 Feb 2026 03:24:00 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id C70566B008C; Thu, 12 Feb 2026 03:24:00 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B89C96B0092; Thu, 12 Feb 2026 03:24:00 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id A81E16B008A for ; Thu, 12 Feb 2026 03:24:00 -0500 (EST) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 47609140731 for ; Thu, 12 Feb 2026 08:24:00 +0000 (UTC) X-FDA: 84435116640.24.5F018FD Received: from out-186.mta1.migadu.com (out-186.mta1.migadu.com [95.215.58.186]) by imf25.hostedemail.com (Postfix) with ESMTP id A64F3A0002 for ; Thu, 12 Feb 2026 08:23:58 +0000 (UTC) Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=HJ0OIcoA; spf=pass (imf25.hostedemail.com: domain of hui.zhu@linux.dev designates 95.215.58.186 as permitted sender) smtp.mailfrom=hui.zhu@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1770884638; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=6JEGc5je/wM02pWehmFOl3sKJ7z0YxNGSRtnUE/RPCI=; b=jaG0JBPTLTX72lceV3Rao8FgQunos/SpS2eo6PPA2Bna6Zr6WbhdesfKhWlSR8/Crj+ELW Zi0BELXvatYNuxMrimIAb3bJuk3dkqYE5xRl0VdA6bOLBOYZwm1e9o7S8i32/EXLwmzyTv 3H+We18a8M4YLzN9yYUmEYfisX1WNPM= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=HJ0OIcoA; spf=pass (imf25.hostedemail.com: domain of hui.zhu@linux.dev designates 95.215.58.186 as permitted sender) smtp.mailfrom=hui.zhu@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1770884638; a=rsa-sha256; cv=none; b=vzKfJcGQnM00xhLgX2bvoyNCfuR/YvqYgTM9LTYhmmsvLg618FqOuPCp5mgGTe/c6A5ySF Xpt8HqtDIhoXArSeahcMh5N5MfnoMwldu64XNGHcWfrshIMAZeFhRolZG5oM9xAQSvA8cA qng3XVC/Bdx1AGaTMGYclx+q/BC5pfE= 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=1770884637; 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=6JEGc5je/wM02pWehmFOl3sKJ7z0YxNGSRtnUE/RPCI=; b=HJ0OIcoA3oOP4U35yiAgKDYaQEY7TuX0qZLIDHgEFaDpBmCxjWW09jCTIjMQzH8JMX5S9F xrjh3BlaT9jvCMCDi44I3clcJ/Li+Q3ml5I/JJo7Viwh8gqwadztOu8XjVc6gL933c7r54 OCbBi0K4vo3sxio7V14h6YbB0bfqkCg= 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 2/3] mm/memcontrol: Return error when accessing kmem with nokmem Date: Thu, 12 Feb 2026 16:23:15 +0800 Message-ID: <733422f72ccbac94126ae67b9e49f4a3d460b76a.1770883926.git.zhuhui@kylinos.cn> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Queue-Id: A64F3A0002 X-Rspamd-Server: rspam07 X-Stat-Signature: ycryx4jzjitppbbpyn35sne1uxeqwn14 X-HE-Tag: 1770884638-216284 X-HE-Meta: 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 xVVMrlr8 yHMCs3cF+VvAhv0QmkZ9T3Tr3SfFP3bln5irFK7VMoFh1yqoVc8oZDHR/TrqsZkvcsa4y2d4WU47KMnOIjEbL6L2hkuOHJhpk4F6QXQntG3TTkcKob/CuKEkZ5WGMEIWeFcerK8dKajF8S2fafOI/joEHKME+CweXjGWzpy5+Z8HGh4oyt7En/cjfYyjkqQMGWN3YGlSVzAoKL+zDlfJmtHkuk3mVUJqlansPIIuSIfuaLsS378Nk/F6ehqISoE+RvbNqouK+yP6tfkQ= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Hui Zhu When running tests on hosts with cgroup.memory=nokmem enabled for performance reasons, test_kmem always gets a value of 0 for kmem statistics. Since BPF programs cannot easily determine whether kmem is enabled, add a check in memcg_stat_item_valid() to return an error when attempting to access MEMCG_KMEM statistics while kmem accounting is disabled via cgroup_memory_nokmem. This prevents BPF programs from silently receiving zero values and allows them to properly handle the case where kmem accounting is unavailable. Signed-off-by: Hui Zhu --- mm/memcontrol.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 129eed3ff5bb..4d8419623d1c 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -667,7 +667,8 @@ unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx) bool memcg_stat_item_valid(int idx) { - if ((u32)idx >= MEMCG_NR_STAT) + if ((u32)idx >= MEMCG_NR_STAT || + (cgroup_memory_nokmem && (u32)idx == MEMCG_KMEM)) return false; return !BAD_STAT_IDX(memcg_stats_index(idx)); -- 2.43.0