When updating local storage maps with BPF_F_LOCK on the fast path, the special fields were not freed after being replaced. This could cause memory referenced by BPF_KPTR_{REF,PERCPU} fields to be held until the map gets freed. Similarly, on the other path, the old sdata's special fields were never freed regardless of whether BPF_F_LOCK was used, causing the same issue. Fix this by calling 'bpf_obj_free_fields()' after 'copy_map_value_locked()' to properly release the old fields. Fixes: 9db44fdd8105 ("bpf: Support kptrs in local storage maps") Signed-off-by: Leon Hwang --- kernel/bpf/bpf_local_storage.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c index b931fbceb54da..8e3aea4e07c50 100644 --- a/kernel/bpf/bpf_local_storage.c +++ b/kernel/bpf/bpf_local_storage.c @@ -609,6 +609,7 @@ bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap, if (old_sdata && selem_linked_to_storage_lockless(SELEM(old_sdata))) { copy_map_value_locked(&smap->map, old_sdata->data, value, false); + bpf_obj_free_fields(smap->map.record, old_sdata->data); return old_sdata; } } @@ -641,6 +642,7 @@ bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap, if (old_sdata && (map_flags & BPF_F_LOCK)) { copy_map_value_locked(&smap->map, old_sdata->data, value, false); + bpf_obj_free_fields(smap->map.record, old_sdata->data); selem = SELEM(old_sdata); goto unlock; } @@ -654,6 +656,7 @@ bpf_local_storage_update(void *owner, struct bpf_local_storage_map *smap, /* Third, remove old selem, SELEM(old_sdata) */ if (old_sdata) { + bpf_obj_free_fields(smap->map.record, old_sdata->data); bpf_selem_unlink_map(SELEM(old_sdata)); bpf_selem_unlink_storage_nolock(local_storage, SELEM(old_sdata), true, &old_selem_free_list); -- 2.51.0