1 files changed, 13 insertions, 0 deletions

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 4f416234251f..53968f82b919 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -748,6 +748,17 @@ err_put:
         return err;
 }
 
+static void maybe_wait_bpf_programs(struct bpf_map *map)
+{
+        /* Wait for any running BPF programs to complete so that
+         * userspace, when we return to it, knows that all programs
+         * that could be running use the new map value.
+         */
+        if (map->map_type == BPF_MAP_TYPE_HASH_OF_MAPS ||
+            map->map_type == BPF_MAP_TYPE_ARRAY_OF_MAPS)
+                synchronize_rcu();
+}
+
 #define BPF_MAP_UPDATE_ELEM_LAST_FIELD flags
 
 static int map_update_elem(union bpf_attr *attr)
@@ -842,6 +853,7 @@ static int map_update_elem(union bpf_attr *attr)
         }
         __this_cpu_dec(bpf_prog_active);
         preempt_enable();
+        maybe_wait_bpf_programs(map);
 out:
 free_value:
         kfree(value);
@@ -894,6 +906,7 @@ static int map_delete_elem(union bpf_attr *attr)
         rcu_read_unlock();
         __this_cpu_dec(bpf_prog_active);
         preempt_enable();
+        maybe_wait_bpf_programs(map);
 out:
         kfree(key);
 err_put: