From nobody Tue Feb 10 00:23:59 2026 Received: from out-173.mta1.migadu.com (out-173.mta1.migadu.com [95.215.58.173]) (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 EE99836EABF for ; Thu, 5 Feb 2026 09:03:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.173 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770282232; cv=none; b=ji5JdV5uRNjhZ8FJzabc7M0HyfiBnGuUJDRS/hxNoB1moymJMjVDj9DhAYTwVgeA7WuY9zndMCycwvxhtb3/ShxmvR20Vzq8G8chCvttDZMbB+23QHjDsBoTc81HvgCcOAiZPZj8DwgE9+XJUWONhTCBdlVcMp3TQeZR9Nfdqto= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770282232; c=relaxed/simple; bh=rA4lTusEzd7HBL3PzjXCY9srrkuV3CpMj7KVY/if2RE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=lF4MmJmzr7wcdLSFdSr4nQROEOcpScbF1i8wT1JCYPSQiZurw6t8tnIlJ0z8YIxumW6Iv+TfHj5G1EscOKZyBjrxvmiIGRxPdCleAxhk9epd4QIyvk0NGAWoZ3MKj7k72FHlUnmXaKP6XuG8sRSORvwO+9LrNXcv+7Fpo9Z/7yY= 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=KVfh9JeK; arc=none smtp.client-ip=95.215.58.173 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="KVfh9JeK" 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=1770282230; 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=JRi+VmXiW8HlsHjnS6VBfEapdpTlECLdprrexkoF+xY=; b=KVfh9JeKpVTMnjxhHqZOl5kWuMUmCKOj23QCvuPn7hKW652FwNQuQF6mDdpkeV27rgECqr ynr8o4Zuwu9IPgsC5o/cHoZT05/tLITASawjRLQR1CHWrNimtaU9i0/mY5LECvobbPE0o7 bP7KqOjQmgjiuffVgrpXepU4iPO8vxs= 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 19/31] mm: workingset: prevent lruvec release in workingset_refault() Date: Thu, 5 Feb 2026 17:01:38 +0800 Message-ID: <20da5d43b253f4810c939aad5ebac0141438271a.1770279888.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_refault(). 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: Shakeel Butt --- mm/workingset.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/mm/workingset.c b/mm/workingset.c index 79b40f058cd48..5fbf316fb0e71 100644 --- a/mm/workingset.c +++ b/mm/workingset.c @@ -539,6 +539,7 @@ bool workingset_test_recent(void *shadow, bool file, bo= ol *workingset, void workingset_refault(struct folio *folio, void *shadow) { bool file =3D folio_is_file_lru(folio); + struct mem_cgroup *memcg; struct lruvec *lruvec; bool workingset; long nr; @@ -560,11 +561,12 @@ void workingset_refault(struct folio *folio, void *sh= adow) * locked to guarantee folio_memcg() stability throughout. */ nr =3D folio_nr_pages(folio); - lruvec =3D folio_lruvec(folio); + memcg =3D get_mem_cgroup_from_folio(folio); + lruvec =3D mem_cgroup_lruvec(memcg, folio_pgdat(folio)); mod_lruvec_state(lruvec, WORKINGSET_REFAULT_BASE + file, nr); =20 if (!workingset_test_recent(shadow, file, &workingset, true)) - return; + goto out; =20 folio_set_active(folio); workingset_age_nonresident(lruvec, nr); @@ -580,6 +582,8 @@ void workingset_refault(struct folio *folio, void *shad= ow) lru_note_cost_refault(folio); mod_lruvec_state(lruvec, WORKINGSET_RESTORE_BASE + file, nr); } +out: + mem_cgroup_put(memcg); } =20 /** --=20 2.20.1