[merged mm-hotfixes-stable] mm-mglru-make-memcg_lru-lock-irq-safe.patch removed from -mm tree

[Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>]

The quilt patch titled
     Subject: mm/mglru: make memcg_lru->lock irq safe
has been removed from the -mm tree.  Its filename was
     mm-mglru-make-memcg_lru-lock-irq-safe.patch

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

------------------------------------------------------
From: Yu Zhao <yuzhao@xxxxxxxxxx>
Subject: mm/mglru: make memcg_lru->lock irq safe
Date: Mon, 19 Jun 2023 13:38:21 -0600

lru_gen_rotate_memcg() can happen in softirq if memory.soft_limit_in_bytes
is set.  This requires memcg_lru->lock to be irq safe.  Lockdep warns on
this.

This problem only affects memcg v1.

Link: https://lkml.kernel.org/r/20230619193821.2710944-1-yuzhao@xxxxxxxxxx
Fixes: e4dde56cd208 ("mm: multi-gen LRU: per-node lru_gen_folio lists")
Signed-off-by: Yu Zhao <yuzhao@xxxxxxxxxx>
Reported-by: syzbot+87c490fd2be656269b6a@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?extid=87c490fd2be656269b6a
Reviewed-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 mm/vmscan.c |   13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

--- a/mm/vmscan.c~mm-mglru-make-memcg_lru-lock-irq-safe
+++ a/mm/vmscan.c
@@ -4728,10 +4728,11 @@ static void lru_gen_rotate_memcg(struct
 {
 	int seg;
 	int old, new;
+	unsigned long flags;
 	int bin = get_random_u32_below(MEMCG_NR_BINS);
 	struct pglist_data *pgdat = lruvec_pgdat(lruvec);
 
-	spin_lock(&pgdat->memcg_lru.lock);
+	spin_lock_irqsave(&pgdat->memcg_lru.lock, flags);
 
 	VM_WARN_ON_ONCE(hlist_nulls_unhashed(&lruvec->lrugen.list));
 
@@ -4766,7 +4767,7 @@ static void lru_gen_rotate_memcg(struct
 	if (!pgdat->memcg_lru.nr_memcgs[old] && old == get_memcg_gen(pgdat->memcg_lru.seq))
 		WRITE_ONCE(pgdat->memcg_lru.seq, pgdat->memcg_lru.seq + 1);
 
-	spin_unlock(&pgdat->memcg_lru.lock);
+	spin_unlock_irqrestore(&pgdat->memcg_lru.lock, flags);
 }
 
 void lru_gen_online_memcg(struct mem_cgroup *memcg)
@@ -4779,7 +4780,7 @@ void lru_gen_online_memcg(struct mem_cgr
 		struct pglist_data *pgdat = NODE_DATA(nid);
 		struct lruvec *lruvec = get_lruvec(memcg, nid);
 
-		spin_lock(&pgdat->memcg_lru.lock);
+		spin_lock_irq(&pgdat->memcg_lru.lock);
 
 		VM_WARN_ON_ONCE(!hlist_nulls_unhashed(&lruvec->lrugen.list));
 
@@ -4790,7 +4791,7 @@ void lru_gen_online_memcg(struct mem_cgr
 
 		lruvec->lrugen.gen = gen;
 
-		spin_unlock(&pgdat->memcg_lru.lock);
+		spin_unlock_irq(&pgdat->memcg_lru.lock);
 	}
 }
 
@@ -4814,7 +4815,7 @@ void lru_gen_release_memcg(struct mem_cg
 		struct pglist_data *pgdat = NODE_DATA(nid);
 		struct lruvec *lruvec = get_lruvec(memcg, nid);
 
-		spin_lock(&pgdat->memcg_lru.lock);
+		spin_lock_irq(&pgdat->memcg_lru.lock);
 
 		VM_WARN_ON_ONCE(hlist_nulls_unhashed(&lruvec->lrugen.list));
 
@@ -4826,7 +4827,7 @@ void lru_gen_release_memcg(struct mem_cg
 		if (!pgdat->memcg_lru.nr_memcgs[gen] && gen == get_memcg_gen(pgdat->memcg_lru.seq))
 			WRITE_ONCE(pgdat->memcg_lru.seq, pgdat->memcg_lru.seq + 1);
 
-		spin_unlock(&pgdat->memcg_lru.lock);
+		spin_unlock_irq(&pgdat->memcg_lru.lock);
 	}
 }
 
_

Patches currently in -mm which might be from yuzhao@xxxxxxxxxx are