The memcg may be the root_mem_cgroup, in which case we shouldn't put it.
So a new helper bpf_map_put_memcg() is introduced to pair with
bpf_map_get_memcg().
Fixes: 4201d9ab3e42 ("bpf: reparent bpf maps on memcg offlining")
Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
---
kernel/bpf/syscall.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 83c7136..51ab8b1 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -441,6 +441,14 @@ static struct mem_cgroup *bpf_map_get_memcg(const struct bpf_map *map)
return root_mem_cgroup;
}
+static void bpf_map_put_memcg(struct mem_cgroup *memcg)
+{
+ if (mem_cgroup_is_root(memcg))
+ return;
+
+ mem_cgroup_put(memcg);
+}
+
void *bpf_map_kmalloc_node(const struct bpf_map *map, size_t size, gfp_t flags,
int node)
{
@@ -451,7 +459,7 @@ void *bpf_map_kmalloc_node(const struct bpf_map *map, size_t size, gfp_t flags,
old_memcg = set_active_memcg(memcg);
ptr = kmalloc_node(size, flags | __GFP_ACCOUNT, node);
set_active_memcg(old_memcg);
- mem_cgroup_put(memcg);
+ bpf_map_put_memcg(memcg);
return ptr;
}
@@ -465,7 +473,7 @@ void *bpf_map_kzalloc(const struct bpf_map *map, size_t size, gfp_t flags)
old_memcg = set_active_memcg(memcg);
ptr = kzalloc(size, flags | __GFP_ACCOUNT);
set_active_memcg(old_memcg);
- mem_cgroup_put(memcg);
+ bpf_map_put_memcg(memcg);
return ptr;
}
@@ -480,7 +488,7 @@ void __percpu *bpf_map_alloc_percpu(const struct bpf_map *map, size_t size,
old_memcg = set_active_memcg(memcg);
ptr = __alloc_percpu_gfp(size, align, flags | __GFP_ACCOUNT);
set_active_memcg(old_memcg);
- mem_cgroup_put(memcg);
+ bpf_map_put_memcg(memcg);
return ptr;
}
--
1.8.3.1
