From nobody Mon Feb 9 19:37:18 2026 Received: from out-172.mta0.migadu.com (out-172.mta0.migadu.com [91.218.175.172]) (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 5BF5A338929; Tue, 28 Oct 2025 14:04:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761660271; cv=none; b=c995w0vE73AKrWaxxEWcdMyh+PMmSRv0vDoJoooGO9mdpIU8eiff9/OFB9u6ZFl6uHZyK230brAlYWfCtJ7UeWUhRGIxbPLrz+Eyu/rAKKEpJ3uagCKnCLcj8Uv1iPry6L1g7Pd+tcZvdpje2r2bgUbbfspPnFUgv/DC0smmFP8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761660271; c=relaxed/simple; bh=0kgT6fzD5akkCPqm03VJrzchYDCochSXofUVtd05LKc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sJy9HJKSi1KJ49biJXJ0l51qqOGE8JpCnRMmcIcbfC3Xz5/lcMWyd68KIXLTaBWf4H5DX/vMYNkrp+ja0lpYLkT2beeg9EYxp3T67ZOKkshZ+p+kRYo/gogRZKNlm1iKa9ubegoWhHzloDPdd0Er4ycNz4d+cUHLbMamzrmdq9Q= 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=GZWIQPg2; arc=none smtp.client-ip=91.218.175.172 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="GZWIQPg2" 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=1761660266; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=MfFT50NAM4YJdcJwEiZWm9eoPKYAch/I/HKN7VyhW9I=; b=GZWIQPg2QKwgut9Dq3hgo3nl0aQwy3J/E5mWPtGNg4bdNwkQ+AI6uq3lfLJklHFfbHo+Pg 3E7xR05XF643Awodwuy+5roySsCLCwXL2xAjK8TTY1IsG7QNx+MN4lIQAYKtvBXnOk8QdZ 7rTdqleL9uVxBl3NuOZLwvW0LxrK80E= From: Qi Zheng To: hannes@cmpxchg.org, hughd@google.com, mhocko@suse.com, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, david@redhat.com, lorenzo.stoakes@oracle.com, ziy@nvidia.com, harry.yoo@oracle.com, imran.f.khan@oracle.com, kamalesh.babulal@oracle.com, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Muchun Song , Qi Zheng Subject: [PATCH v1 20/26] mm: workingset: prevent lruvec release in workingset_activation() Date: Tue, 28 Oct 2025 21:58:33 +0800 Message-ID: <03a26f7d8723a42c29a24b03ed318a2830faff02.1761658311.git.zhengqi.arch@bytedance.com> 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: Muchun Song In the near future, a folio will no longer pin its corresponding memory cgroup. So an lruvec returned by folio_lruvec() could be released without the rcu read lock or a reference to its memory cgroup. In the current patch, the rcu read lock is employed to safeguard against the release of the lruvec in workingset_activation(). This serves as a preparatory measure for the reparenting of the LRU pages. Signed-off-by: Muchun Song Signed-off-by: Qi Zheng Reviewed-by: Harry Yoo --- mm/workingset.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/mm/workingset.c b/mm/workingset.c index a69cc7bf9246d..d0eb3636dcd1d 100644 --- a/mm/workingset.c +++ b/mm/workingset.c @@ -595,8 +595,11 @@ void workingset_activation(struct folio *folio) * Filter non-memcg pages here, e.g. unmap can call * mark_page_accessed() on VDSO pages. */ - if (mem_cgroup_disabled() || folio_memcg_charged(folio)) + if (mem_cgroup_disabled() || folio_memcg_charged(folio)) { + rcu_read_lock(); workingset_age_nonresident(folio_lruvec(folio), folio_nr_pages(folio)); + rcu_read_unlock(); + } } =20 /* --=20 2.20.1