Re: [PATCH] fix: mm: memcontrol: convert objcg to be per-memcg per-node type
From: Qi Zheng
Date: Mon Mar 09 2026 - 07:44:43 EST
On 3/9/26 7:33 PM, Usama Arif wrote:
On 09/03/2026 14:29, Qi Zheng wrote:
From: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Reset pn->orig_objcg to NULL to prevent obj_cgroup_put()
from being called agagin in __mem_cgroup_free().
Reported-by: Usama Arif <usama.arif@xxxxxxxxx>
Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
---
mm/memcontrol.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 992a3f5caa62b..ad32639ea5959 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4140,8 +4140,14 @@ static int mem_cgroup_css_online(struct cgroup_subsys_state *css)
for_each_node(nid) {
struct mem_cgroup_per_node *pn = memcg->nodeinfo[nid];
- if (pn && pn->orig_objcg)
+ if (pn && pn->orig_objcg) {
obj_cgroup_put(pn->orig_objcg);
+ /*
+ * Reset pn->orig_objcg to NULL to prevent obj_cgroup_put()
+ * from being called agagin in __mem_cgroup_free().
nit: s/agagin/again/
Ouch, my bad.
Hi Andrew, can you help squash the following diff:
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index ad32639ea5959..5fcbb651846a4 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4144,7 +4144,7 @@ static int mem_cgroup_css_online(struct cgroup_subsys_state *css)
obj_cgroup_put(pn->orig_objcg);
/*
* Reset pn->orig_objcg to NULL to prevent obj_cgroup_put()
- * from being called agagin in __mem_cgroup_free().
+ * from being called again in __mem_cgroup_free().
*/
pn->orig_objcg = NULL;
}
Apart from the nit.
Acked-by: Usama Arif <usama.arif@xxxxxxxxx>
Thanks!
+ */
+ pn->orig_objcg = NULL;
+ }
}
free_shrinker_info(memcg);
offline_kmem: