From nobody Mon Feb 9 16:12:33 2026 Received: from out-171.mta0.migadu.com (out-171.mta0.migadu.com [91.218.175.171]) (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 6A1A7395DA4 for ; Wed, 14 Jan 2026 11:35:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.171 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768390503; cv=none; b=HvAHoYwFs7DlZLIh9BDex89JuQ2NkkFCpSND75ySxLwyk0XMSdgp3XSv1xB2Bdx1WFo1MNLbNsgYhpi1LufJJI7aWmLS6idA12988nSwP3c+LwmJKDthFuwWDEMIF60U7wS0scg+iGMYqbkceePSEP7LZapLDXIAiIcGZ1+rpyc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768390503; c=relaxed/simple; bh=j2FfyK9UgxuVE09vP3zIAqH+vMQqCpo1ZFoDT1zn5NE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hltMQ7wvREpE6hOTW3vaD74aickFlzEDls+oD/EBlX37Ntor4vBEuzeHrDVsf+LI4/hvLIhPqqQBiXCfpG6oA+PBHhKhueKtgXuL7sCNddZkrT/AUmUL2UZeDuR3v0YwRFnwE28iJz2+X2VQ9tYhNVR+ZyklPAb+LFVHSFbBytw= 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=rw7+XHFV; arc=none smtp.client-ip=91.218.175.171 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="rw7+XHFV" 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=1768390499; 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=8TLeP7fYOzu8/cJlnQSSB8V8+h3N7MMe0p0E2AHA8PY=; b=rw7+XHFV0L/y5GA9znQNDkAe7IicOiDLmxagEGb7+dZPAPOVII+pgArZiTxva6G01ZebIk 8AJcfB6VOc43hNFJDZVo3F8uWsdya2f9aC5SM7ttlnDm4Mf3g47qvVtdreFTK/P7Y4vwOA HjeTb9SR8xXnY8pdUBXHjZ9ueZ1Yi2I= 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 Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Muchun Song , Qi Zheng Subject: [PATCH v3 19/30] mm: workingset: prevent lruvec release in workingset_refault() Date: Wed, 14 Jan 2026 19:32:46 +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_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