The patch titled
Subject: mm/mglru: make memcg_lru->lock irq safe
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-mglru-make-memcg_lru-lock-irq-safe.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mglru-make-memcg_lru-lock-irq-safe.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
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.
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
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
@@ -4743,10 +4743,11 @@ 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));
@@ -4781,7 +4782,7 @@ 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)
@@ -4794,7 +4795,7 @@ 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));
@@ -4805,7 +4806,7 @@ 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);
}
}
@@ -4829,7 +4830,7 @@ 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));
@@ -4841,7 +4842,7 @@ 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
mm-mglru-make-memcg_lru-lock-irq-safe.patch
