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 9722637AA86; Tue, 28 Apr 2026 22:12:54 +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=1777414374; cv=none; b=ly80DBWKtHz1dN/Z48b6fP5peNdr3Kub7oadhTYMOher5Zmi4wEiossNIYaI8fZ8F2xwfJp51A9diKUDyT5NxnAVPJKityls1F/tRSoOghJxD+KG17xiktdkLvoVd02YAanRUPHeZREdh09d6Jzt4IkeXgTGW0B7JRau8JUutH8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777414374; c=relaxed/simple; bh=kkg+9dj6Kg2m+RboFcKUDNE4w+XzBqWMxSts1BhV6I4=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=IyCHZ5BDAkUr5WKBCTOBGwFkKF1i5XWlI/60Q5jk60ZCLypmYedIdUnY5p+4XyQkaRr8WraCON7AtdXIsfuCDfc+0O40ZZB2xLSsu8spS7SokfmByCmYrBXFP2zVX1Gr8Zkbz7D562ZTLAKNpzuIET5VtHlYgU8DIsiTB0dSGTo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=XNpnAMES; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="XNpnAMES" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DB121C2BCAF; Tue, 28 Apr 2026 22:12:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1777414374; bh=kkg+9dj6Kg2m+RboFcKUDNE4w+XzBqWMxSts1BhV6I4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=XNpnAMES5OC4zofWEQ9KsfRL5J+zTlmIOclCucf7XWL26Ni9y2W9YOCHeIz4luJxW 6epdhnr0Ye6sH711e47Tlb8kS31HcY0e+SY+dZqW8c30qVDfqDpzZUDcKjrQCHSjD5 IFOoeMtYNvW5gut/7PMoK6wqunXzLTWN86Q4Xl3w= Date: Tue, 28 Apr 2026 15:12:53 -0700 From: Andrew Morton To: Qi Zheng Cc: hannes@cmpxchg.org, mhocko@kernel.org, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, yosry@kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Qi Zheng Subject: Re: [PATCH v2] mm: memcontrol: fix rcu unbalance in get_non_dying_memcg_end() Message-Id: <20260428151253.bdfb08401ebb74c438df0e52@linux-foundation.org> In-Reply-To: <20260428103108.45719-1-qi.zheng@linux.dev> References: <20260428103108.45719-1-qi.zheng@linux.dev> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Tue, 28 Apr 2026 18:31:08 +0800 Qi Zheng wrote: > Currently, get_non_dying_memcg_start() and get_non_dying_memcg_end() both > evaluate cgroup_subsys_on_dfl(memory_cgrp_subsys) independently to > determine whether to acquire or release the RCU read lock. Sashiko review (https://sashiko.dev/#/patchset/20260428103108.45719-1-qi.zheng@linux.dev) is correct. mm/memcontrol.c: In function 'mod_memcg_state': mm/memcontrol.c:881:9: error: 'rcu_locked' is used uninitialized [-Werror=uninitialized] 881 | get_non_dying_memcg_end(rcu_locked); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ mm/memcontrol.c:874:14: note: 'rcu_locked' was declared here 874 | bool rcu_locked; | ^~~~~~~~~~ In function 'mod_memcg_lruvec_state', inlined from 'mod_lruvec_state' at mm/memcontrol.c:973:3: mm/memcontrol.c:952:9: error: 'rcu_locked' is used uninitialized [-Werror=uninitialized] 952 | get_non_dying_memcg_end(rcu_locked); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ mm/memcontrol.c:944:14: note: 'rcu_locked' was declared here 944 | bool rcu_locked; | ^~~~~~~~~~ In function 'mod_memcg_state', inlined from 'mem_cgroup_sk_uncharge' at mm/memcontrol.c:5392:2: mm/memcontrol.c:881:9: error: 'rcu_locked' is used uninitialized [-Werror=uninitialized] 881 | get_non_dying_memcg_end(rcu_locked); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ mm/memcontrol.c:874:14: note: 'rcu_locked' was declared here 874 | bool rcu_locked; | ^~~~~~~~~~