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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: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Stat-Signature: 5obp5mhehj4g1zqdnconxw5xu69knwd3 X-Rspamd-Queue-Id: 64FBE180004 X-Rspamd-Server: rspam03 X-HE-Tag: 1772711859-592272 X-HE-Meta: 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 yRKrTumi z0TLVDV0UaosbP/mpNj0CpbK+rlcAx2Y1+n1ZU2M6Gq3sl1VviwhHKYudnfjw74mDV4HlsWYme8Fhe2d933Hbl5Z5JTsKBVH1SYiUIOqXyZh5IkKvSa7zhJpDYdwatPWRcnawpAaobCsKFSAIe7RLsUDHrIa6KHNy/aqBnvE9nC25/g68R3OQErX1VEeq82rF3dVnbanzwWImSr6ouUvS3usAyRcyyoINhSouWOzqzPARpW6ITknv1ntF5mMDYaZiMpFY8LYwiyVqCG8W3g42B9moPNFousQVr5nJPWwKInTVKLHYQr1Tai5bpEodg/r8xR7z/I9BsFGTAy8vDeXzbnCRcw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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; if (folio) { + rcu_read_lock(); lruvec = folio_lruvec(folio); atomic_long_inc(&lruvec->zswap_lruvec_state.nr_disk_swapins); + rcu_read_unlock(); } } -- 2.20.1