The commit is pushed to "branch-rh10-6.12.0-55.13.1.vz10.2.x-ovz" and will
appear at g...@bitbucket.org:openvz/vzkernel.git
after rh10-6.12.0-55.13.1.el10
------>
commit 333f254f205b2bd67140f3923806347af62f66cb
Author: Pavel Tikhomirov <ptikhomi...@virtuozzo.com>
Date: Mon Aug 4 11:29:48 2025 +0800
mm: fix negative dentry accounting by protecting memcg with rcu_read_lock
This fixes the warning:
WARNING: CPU: 0 PID: 1 at include/linux/memcontrol.h:404
mem_cgroup_from_slab_obj+0x426/0x580
In this stack:
+-> dput
+-> __dentry_kill
+-> d_lru_del
+-> memcg_neg_dentry_dec
+-> mem_cgroup_from_slab_obj
+-> mem_cgroup_from_obj_folio
+-> obj_cgroup_memcg
Detected when running xfstests-generic/321.
https://virtuozzo.atlassian.net/browse/VSTOR-112802
Fixes: 2b4edb1f998a ("mm: per-memcg negative dentries accounting")
Signed-off-by: Pavel Tikhomirov <ptikhomi...@virtuozzo.com>
Feature: mm: statistic enhancements
---
mm/memcontrol.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 175d43481c6f2..3563586ff93fd 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3240,18 +3240,24 @@ unsigned long mem_cgroup_read_nd(struct mem_cgroup
*memcg)
void memcg_neg_dentry_inc(struct dentry *dentry)
{
- struct mem_cgroup *memcg = mem_cgroup_from_slab_obj(dentry);
+ struct mem_cgroup *memcg;
+ rcu_read_lock();
+ memcg = mem_cgroup_from_slab_obj(dentry);
if (memcg)
__this_cpu_inc(memcg->vmstats_percpu->nr_dentry_neg);
+ rcu_read_unlock();
}
void memcg_neg_dentry_dec(struct dentry *dentry)
{
- struct mem_cgroup *memcg = mem_cgroup_from_slab_obj(dentry);
+ struct mem_cgroup *memcg;
+ rcu_read_lock();
+ memcg = mem_cgroup_from_slab_obj(dentry);
if (memcg)
__this_cpu_dec(memcg->vmstats_percpu->nr_dentry_neg);
+ rcu_read_unlock();
}
/*
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