From nobody Tue Feb 10 00:59:32 2026 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 28BF238F257 for ; Thu, 5 Feb 2026 09:04:18 +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=1770282258; cv=none; b=r4mH5tVPDOFjgrWYKSLcq9iDNlNDKMFGtV1VaY/CLbp8CzyDXLoHhroQF8X7bBO6K2hepb+LHll7ZELtUBmOOoHEqY5BS1d5RcSG9Hhu8U+YGwhQ8qRUoQq3HLR1je7HVnQA0hW7JfkRvyONmKa6R9cUJY+tvqFEPsV7fSMSGxI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770282258; c=relaxed/simple; bh=69SJwUfil99/bsWDx2B0ReWvIk5L/eXzjcW37K7MxwY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=i/L4F2g8nnTwNzHVryUJC82/n8n52roJ0O8K9xIYpFyz50QVszvkA49VpzfHTBWi8azW748wqmoivN/kpStFKMMmoi4sG07k5X3aJXStFCeYFdexUZEMkTImpzNVxjtqtUCcSUz0/8iVirOvWHVYSLIjrYAcd/ZjeJEUUMSopIw= 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=bMMa+8pR; 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="bMMa+8pR" 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=1770282255; 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=Z51xqOUPrAhoh0O0GpdBH64DgayE69nJ4AY48cemOmg=; b=bMMa+8pRpvMevU5o7P6NsU1IxXKTc+bvGFohw4xmiWOB37yVdObh8wFaj4uWDIL8ZP0Ajf l25CZigM/807YogavESysrH/Fa5HpUiF38wM17snFCM7yXjs1qL4CKd9xHKhMhXOz1dkqN aorEwUkDMctoafCw7zpiPl1aPvRpcS8= 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@kernel.org, lorenzo.stoakes@oracle.com, ziy@nvidia.com, harry.yoo@oracle.com, yosry.ahmed@linux.dev, imran.f.khan@oracle.com, kamalesh.babulal@oracle.com, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, chenridong@huaweicloud.com, mkoutny@suse.com, akpm@linux-foundation.org, hamzamahfooz@linux.microsoft.com, apais@linux.microsoft.com, lance.yang@linux.dev, bhe@redhat.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Muchun Song , Qi Zheng Subject: [PATCH v4 22/31] mm: workingset: prevent lruvec release in workingset_activation() Date: Thu, 5 Feb 2026 17:01:41 +0800 Message-ID: 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 Acked-by: Johannes Weiner Acked-by: Shakeel Butt --- mm/workingset.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/mm/workingset.c b/mm/workingset.c index 5fbf316fb0e71..2be53098f6282 100644 --- a/mm/workingset.c +++ b/mm/workingset.c @@ -596,8 +596,11 @@ 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