From 645d5d3bc001a7d77459cb8360c36a60954d6008 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Tue, 5 Jul 2022 15:48:16 -0700 Subject: [PATCH] selftests/bpf: Fix bogus uninitialized variable warning MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When compiling selftests/bpf in optimized mode (-O2), GCC erroneously complains about uninitialized token variable: In file included from network_helpers.c:22: network_helpers.c: In function ‘open_netns’: test_progs.h:355:22: error: ‘token’ may be used uninitialized [-Werror=maybe-uninitialized] 355 | int ___err = libbpf_get_error(___res); \ | ^~~~~~~~~~~~~~~~~~~~~~~~ network_helpers.c:440:14: note: in expansion of macro ‘ASSERT_OK_PTR’ 440 | if (!ASSERT_OK_PTR(token, "malloc token")) | ^~~~~~~~~~~~~ In file included from /data/users/andriin/linux/tools/testing/selftests/bpf/tools/include/bpf/libbpf.h:21, from bpf_util.h:9, from network_helpers.c:20: /data/users/andriin/linux/tools/testing/selftests/bpf/tools/include/bpf/libbpf_legacy.h:113:17: note: by argument 1 of type ‘const void *’ to ‘libbpf_get_error’ declared here 113 | LIBBPF_API long libbpf_get_error(const void *ptr); | ^~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors make: *** [Makefile:522: /data/users/andriin/linux/tools/testing/selftests/bpf/network_helpers.o] Error 1 This is completely bogus becuase libbpf_get_error() doesn't dereference pointer, but the only easy way to silence this is to allocate initialized memory with calloc(). Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Acked-by: Yonghong Song Acked-by: Jiri Olsa Link: https://lore.kernel.org/bpf/20220705224818.4026623-2-andrii@kernel.org --- tools/testing/selftests/bpf/network_helpers.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c index 59cf81ec55af..bec15558fd93 100644 --- a/tools/testing/selftests/bpf/network_helpers.c +++ b/tools/testing/selftests/bpf/network_helpers.c @@ -436,7 +436,7 @@ struct nstoken *open_netns(const char *name) int err; struct nstoken *token; - token = malloc(sizeof(struct nstoken)); + token = calloc(1, sizeof(struct nstoken)); if (!ASSERT_OK_PTR(token, "malloc token")) return NULL;