git.openwrt.org Git - openwrt/staging/yousong.git/blob

   1 From 74d0dcf7608b1bab116e297468ac51b57eb97ce0 Mon Sep 17 00:00:00 2001
   2 From: Tony Ambardar <Tony.Ambardar@gmail.com>
   3 Date: Thu, 20 Aug 2020 10:06:24 -0700
   4 Subject: [PATCH] libbpf: fix build failure from uninitialized variable warning
   5
   6 While compiling libbpf, some GCC versions (at least 8.4.0) have difficulty
   7 determining control flow and a emit warning for potentially uninitialized
   8 usage of 'map', which results in a build error if using "-Werror":
   9
  10 In file included from libbpf.c:56:
  11 libbpf.c: In function '__bpf_object__open':
  12 libbpf_internal.h:59:2: warning: 'map' may be used uninitialized in this function [-Wmaybe-uninitialized]
  13   libbpf_print(level, "libbpf: " fmt, ##__VA_ARGS__); \
  14   ^~~~~~~~~~~~
  15 libbpf.c:5032:18: note: 'map' was declared here
  16   struct bpf_map *map, *targ_map;
  17                   ^~~
  18
  19 The warning/error is false based on code inspection, so silence it with a
  20 NULL initialization.
  21
  22 Fixes: 646f02ffdd49 ("libbpf: Add BTF-defined map-in-map support")
  23 Ref: 063e68813391 ("libbpf: Fix false uninitialized variable warning")
  24
  25 Signed-off-by: Tony Ambardar <Tony.Ambardar@gmail.com>
  26 ---
  27  tools/lib/bpf/libbpf.c | 2 +-
  28  1 file changed, 1 insertion(+), 1 deletion(-)
  29
  30 diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
  31 index 11e4725b8b1c..a72296797357 100644
  32 --- a/tools/lib/bpf/libbpf.c
  33 +++ b/tools/lib/bpf/libbpf.c
  34 @@ -5028,8 +5028,8 @@ static int bpf_object__collect_map_relos(struct bpf_object *obj,
  35         int i, j, nrels, new_sz, ptr_sz = sizeof(void *);
  36         const struct btf_var_secinfo *vi = NULL;
  37         const struct btf_type *sec, *var, *def;
  38 +       struct bpf_map *map = NULL, *targ_map;
  39         const struct btf_member *member;
  40 -       struct bpf_map *map, *targ_map;
  41         const char *name, *mname;
  42         Elf_Data *symbols;
  43         unsigned int moff;
  44 --
  45 2.25.1
  46