selftests/bpf: Fix a compilation warning

The following warning is triggered when I used clang compiler
to build the selftest.

  /.../prog_tests/btf_dedup_split.c:368:6: warning: variable 'btf2' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
        if (!ASSERT_OK(err, "btf_dedup"))
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
  /.../prog_tests/btf_dedup_split.c:424:12: note: uninitialized use occurs here
        btf__free(btf2);
                  ^~~~
  /.../prog_tests/btf_dedup_split.c:368:2: note: remove the 'if' if its condition is always false
        if (!ASSERT_OK(err, "btf_dedup"))
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  /.../prog_tests/btf_dedup_split.c:343:25: note: initialize the variable 'btf2' to silence this warning
        struct btf *btf1, *btf2;
                               ^
                                = NULL

Initialize local variable btf2 = NULL and the warning is gone.

Fixes: 9a49afe6f5a5 ("selftests/bpf: Add btf_dedup case with duplicated structs within CU")
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211209050403.1770836-1-yhs@fb.com

diff --git a/tools/testing/selftests/bpf/prog_tests/btf_dedup_split.c b/tools/testing/selftests/bpf/prog_tests/btf_dedup_split.c
index 878a864dae3b5190831e7e53748e37c4bac22d31..90aac437576d4cfc67311a29bbd8351ecb6f5f05 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/btf_dedup_split.c
+++ b/tools/testing/selftests/bpf/prog_tests/btf_dedup_split.c
@@ -340,7 +340,7 @@ static void btf_add_dup_struct_in_cu(struct btf *btf, int start_id)
 
 static void test_split_dup_struct_in_cu()
 {
-       struct btf *btf1, *btf2;
+       struct btf *btf1, *btf2 = NULL;
        int err;
 
        /* generate the base data.. */