From 1c904089319512706985e379d992f9bf05bfc645 Mon Sep 17 00:00:00 2001 From: Yu Zhao Date: Mon, 19 Jun 2023 13:38:21 -0600 Subject: [PATCH] UPSTREAM: mm/mglru: make memcg_lru->lock irq safe 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. Bug: 254441685 Link: https://lkml.kernel.org/r/20230619193821.2710944-1-yuzhao@google.com Fixes: e4dde56cd208 ("mm: multi-gen LRU: per-node lru_gen_folio lists") Signed-off-by: Yu Zhao Reported-by: syzbot+87c490fd2be656269b6a@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=87c490fd2be656269b6a Reviewed-by: Yosry Ahmed Cc: Signed-off-by: Andrew Morton (cherry picked from commit 814bc1de03ea4361101408e63a68e4b82aef22cb) Signed-off-by: Lee Jones Change-Id: I8ae02e92135faad78be6509c3bf18109b0f97a13 --- mm/vmscan.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index de0a079c029f..001767ecf169 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -4702,10 +4702,11 @@ static void lru_gen_rotate_memcg(struct lruvec *lruvec, int op) { 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)); @@ -4740,7 +4741,7 @@ static void lru_gen_rotate_memcg(struct lruvec *lruvec, int op) 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) @@ -4753,7 +4754,7 @@ void lru_gen_online_memcg(struct mem_cgroup *memcg) 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)); @@ -4764,7 +4765,7 @@ void lru_gen_online_memcg(struct mem_cgroup *memcg) lruvec->lrugen.gen = gen; - spin_unlock(&pgdat->memcg_lru.lock); + spin_unlock_irq(&pgdat->memcg_lru.lock); } } @@ -4788,7 +4789,7 @@ void lru_gen_release_memcg(struct mem_cgroup *memcg) 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)); @@ -4800,7 +4801,7 @@ void lru_gen_release_memcg(struct mem_cgroup *memcg) 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); } }