From: Pu Lehui <pulehui@xxxxxxxxxx>
Commit 70294d8bc31f ("bpf: Eliminate rlimit-based memory accounting for
devmap maps") relies on the v5.11+ basic mechanism of memcg-based memory
accounting [0]. The commit cannot be independently backported to the
5.10 stable branch, otherwise the related memory when creating devmap
will be unrestricted and the associated bpf selftest map_ptr will fail.
Let's roll back to rlimit-based memory accounting mode for devmap and
re-adapt the commit 225da02acdc9 ("bpf: Fix DEVMAP_HASH overflow check
on 32-bit arches") to the 5.10 stable branch.
Link: https://lore.kernel.org/bpf/20201201215900.3569844-1-guro@xxxxxx [0]
Fixes: 225da02acdc9 ("bpf: Fix DEVMAP_HASH overflow check on 32-bit arches")
Fixes: 70294d8bc31f ("bpf: Eliminate rlimit-based memory accounting for devmap maps")
Signed-off-by: Pu Lehui <pulehui@xxxxxxxxxx>
---
kernel/bpf/devmap.c | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index 07b5edb2c70f..7eb1282edc8e 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -109,6 +109,8 @@ static inline struct hlist_head *dev_map_index_hash(struct bpf_dtab *dtab,
static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)
{
u32 valsize = attr->value_size;
+ u64 cost = 0;
+ int err;
/* check sanity of attributes. 2 value sizes supported:
* 4 bytes: ifindex
@@ -136,11 +138,21 @@ static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)
return -EINVAL;
dtab->n_buckets = roundup_pow_of_two(dtab->map.max_entries);
+ cost += (u64) sizeof(struct hlist_head) * dtab->n_buckets;
+ } else {
+ cost += (u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *);
+ }
+ /* if map size is larger than memlock limit, reject it */
+ err = bpf_map_charge_init(&dtab->map.memory, cost);
+ if (err)
+ return -EINVAL;
+
+ if (attr->map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
dtab->dev_index_head = dev_map_create_hash(dtab->n_buckets,
dtab->map.numa_node);
if (!dtab->dev_index_head)
- return -ENOMEM;
+ goto free_charge;
spin_lock_init(&dtab->index_lock);
} else {
@@ -148,10 +160,14 @@ static int dev_map_init_map(struct bpf_dtab *dtab, union bpf_attr *attr)
sizeof(struct bpf_dtab_netdev *),
dtab->map.numa_node);
if (!dtab->netdev_map)
- return -ENOMEM;
+ goto free_charge;
}
return 0;
+
+free_charge:
+ bpf_map_charge_finish(&dtab->map.memory);
+ return -ENOMEM;
}
static struct bpf_map *dev_map_alloc(union bpf_attr *attr)
--
2.34.1
