From nobody Thu Apr 2 00:15:09 2026 Received: from out-189.mta0.migadu.com (out-189.mta0.migadu.com [91.218.175.189]) (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 91FBA38424E; Thu, 5 Mar 2026 11:57:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.189 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772711860; cv=none; b=g9MmDwHvPvDg0yvitr4vRmzSk2t4Rh8y/WmdrnaRJbSpBGHp892kRx/StMbUa6HEWvoewqHEVjeK3bXmG3ahM1IqpMQjIyJO10rl4wSnwk1m6dpkMVM6Bvjj0EOCIAKI6TymknRc1G3ghlwdAgqGaWrLqPirHt6Y0Hcy8qCz1ew= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772711860; c=relaxed/simple; bh=dR/vbyqOb8a7p0boP0y2ACe1ICZlx8mPQUnTtGDzDgg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bDx2jxVXqcZKmwVp3kVk+A+y5r/63NTH7XKsztKoN//xVh4BktnIRafPDGMk/5JVMB+vohF6Ayno2QCm/a6gH5X13umdotifraP2E9O78VZ+mSegRybXWWEQ14c2wmzzl1LVNuqdDGzX8lws/o7j95m6dscEpeyxtjplNJohrpc= 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=D5G9LhV9; arc=none smtp.client-ip=91.218.175.189 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="D5G9LhV9" 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=1772711857; 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=jmuZGex7AAaN+LnMc+A6Q6xc1gQPncq5PZ4nPQh5Rck=; b=D5G9LhV9i9D+g8zOKEs6s94sZHQteuhZZQvtZYE5qwK9GZ7kfNcLpYygIw0aL1xzHzwQ7H qo3NIicbH0E9eBQhnms0uu/Ctl6xOdp5PuA/td0lZLaXnbWyCF1loex70Eb/PwO0pqB2b6 D5pea089i0q7vev0/I3J2Cj7sSfCois= 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, usamaarif642@gmail.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Muchun Song , Nhat Pham , Chengming Zhou , Qi Zheng Subject: [PATCH v6 20/33] mm: zswap: prevent lruvec release in zswap_folio_swapin() Date: Thu, 5 Mar 2026 19:52:38 +0800 Message-ID: <02b3f76ee8d1132f69ac5baaedce38fb82b09a48.1772711148.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 zswap_folio_swapin(). This serves as a preparatory measure for the reparenting of the LRU pages. Signed-off-by: Muchun Song Acked-by: Nhat Pham Reviewed-by: Chengming Zhou Signed-off-by: Qi Zheng Reviewed-by: Harry Yoo Acked-by: Johannes Weiner Acked-by: Shakeel Butt --- mm/zswap.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/zswap.c b/mm/zswap.c index fb525874a1b6b..bdd24430f6ff2 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -664,8 +664,10 @@ void zswap_folio_swapin(struct folio *folio) struct lruvec *lruvec; =20 if (folio) { + rcu_read_lock(); lruvec =3D folio_lruvec(folio); atomic_long_inc(&lruvec->zswap_lruvec_state.nr_disk_swapins); + rcu_read_unlock(); } } =20 --=20 2.20.1