Upgrade to 4.4.50-rt62

[kvmfornfv.git] / kernel / kernel / bpf / syscall.c

diff --git a/kernel/kernel/bpf/syscall.c b/kernel/kernel/bpf/syscall.c
index 3b39550..4e32cc9 100644 (file)
--- a/kernel/kernel/bpf/syscall.c
+++ b/kernel/kernel/bpf/syscall.c
@@ -181,11 +181,18 @@ struct bpf_map *__bpf_map_get(struct fd f)
        return f.file->private_data;
 }
 
-void bpf_map_inc(struct bpf_map *map, bool uref)
+/* prog's and map's refcnt limit */
+#define BPF_MAX_REFCNT 32768
+
+struct bpf_map *bpf_map_inc(struct bpf_map *map, bool uref)
 {
-       atomic_inc(&map->refcnt);
+       if (atomic_inc_return(&map->refcnt) > BPF_MAX_REFCNT) {
+               atomic_dec(&map->refcnt);
+               return ERR_PTR(-EBUSY);
+       }
        if (uref)
                atomic_inc(&map->usercnt);
+       return map;
 }
 
 struct bpf_map *bpf_map_get_with_uref(u32 ufd)
@@ -197,7 +204,7 @@ struct bpf_map *bpf_map_get_with_uref(u32 ufd)
        if (IS_ERR(map))
                return map;
 
-       bpf_map_inc(map, true);
+       map = bpf_map_inc(map, true);
        fdput(f);
 
        return map;
@@ -580,6 +587,15 @@ static struct bpf_prog *__bpf_prog_get(struct fd f)
        return f.file->private_data;
 }
 
+struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog)
+{
+       if (atomic_inc_return(&prog->aux->refcnt) > BPF_MAX_REFCNT) {
+               atomic_dec(&prog->aux->refcnt);
+               return ERR_PTR(-EBUSY);
+       }
+       return prog;
+}
+
 /* called by sockets/tracing/seccomp before attaching program to an event
  * pairs with bpf_prog_put()
  */
@@ -592,7 +608,7 @@ struct bpf_prog *bpf_prog_get(u32 ufd)
        if (IS_ERR(prog))
                return prog;
 
-       atomic_inc(&prog->aux->refcnt);
+       prog = bpf_prog_inc(prog);
        fdput(f);
 
        return prog;