[merged mm-stable] mm-zswap-prevent-lruvec-release-in-zswap_folio_swapin.patch removed from -mm tree

[merged mm-stable] mm-zswap-prevent-lruvec-release-in-zswap_folio_swapin.patch removed from -mm tree

[Andrew Morton]

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The quilt patch titled
     Subject: mm: zswap: prevent lruvec release in zswap_folio_swapin()
has been removed from the -mm tree.  Its filename was
     mm-zswap-prevent-lruvec-release-in-zswap_folio_swapin.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Muchun Song <songmuchun@bytedance.com>
Subject: mm: zswap: prevent lruvec release in zswap_folio_swapin()
Date: Thu, 5 Mar 2026 19:52:38 +0800

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.

Link: https://lore.kernel.org/02b3f76ee8d1132f69ac5baaedce38fb82b09a48.1772711148.git.zhengqi.arch@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>
Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Allen Pais <apais@linux.microsoft.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Chen Ridong <chenridong@huawei.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Hamza Mahfooz <hamzamahfooz@linux.microsoft.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Imran Khan <imran.f.khan@oracle.com>
Cc: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Xu <weixugc@google.com>
Cc: Yosry Ahmed <yosry@kernel.org>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/zswap.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/mm/zswap.c~mm-zswap-prevent-lruvec-release-in-zswap_folio_swapin
+++ a/mm/zswap.c
@@ -664,8 +664,10 @@ void zswap_folio_swapin(struct folio *fo
 	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();
 	}
 }
 
_

Patches currently in -mm which might be from songmuchun@bytedance.com are