selftests/bpf: Fix GCC11 compiler warnings in -O2 mode

When compiling selftests in -O2 mode with GCC1, we get three new
compilations warnings about potentially uninitialized variables.

Compiler is wrong 2 out of 3 times, but this patch makes GCC11 happy
anyways, as it doesn't cost us anything and makes optimized selftests
build less annoying.

The amazing one is tc_redirect case of token that is malloc()'ed before
ASSERT_OK_PTR() check is done on it. Seems like GCC pessimistically
assumes that libbpf_get_error() will dereference the contents of the
pointer (no it won't), so the only way I found to shut GCC up was to do
zero-initializaing calloc(). This one was new to me.

For linfo case, GCC didn't realize that linfo_size will be initialized
by the function that is returning linfo_size as out parameter.

core_reloc.c case was a real bug, we can goto cleanup before initializing
obj. But we don't need to do any clean up, so just continue iteration
intstead.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220211190927.1434329-1-andrii@kernel.org

diff --git a/tools/testing/selftests/bpf/prog_tests/btf.c b/tools/testing/selftests/bpf/prog_tests/btf.c
index 8b652f5ce423946a0347d439cb2837efb26d7794..ec823561b912fabdd06828abeb889d2ddac0d435 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/btf.c
+++ b/tools/testing/selftests/bpf/prog_tests/btf.c
@@ -6556,7 +6556,7 @@ done:
 static void do_test_info_raw(unsigned int test_num)
 {
        const struct prog_info_raw_test *test = &info_raw_tests[test_num - 1];
-       unsigned int raw_btf_size, linfo_str_off, linfo_size;
+       unsigned int raw_btf_size, linfo_str_off, linfo_size = 0;
        int btf_fd = -1, prog_fd = -1, err = 0;
        void *raw_btf, *patched_linfo = NULL;
        const char *ret_next_str;

diff --git a/tools/testing/selftests/bpf/prog_tests/core_reloc.c b/tools/testing/selftests/bpf/prog_tests/core_reloc.c
index b8bdd1c3efcaa54628a165599f0e82bdbfd35d21..68e4c8dafa00190c1fcd0f4ae7fd7c429b4a0866 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/core_reloc.c
+++ b/tools/testing/selftests/bpf/prog_tests/core_reloc.c
@@ -872,7 +872,7 @@ void test_core_reloc(void)
                if (test_case->btf_src_file) {
                        err = access(test_case->btf_src_file, R_OK);
                        if (!ASSERT_OK(err, "btf_src_file"))
-                               goto cleanup;
+                               continue;
                }
 
                open_opts.btf_custom_path = test_case->btf_src_file;

diff --git a/tools/testing/selftests/bpf/prog_tests/tc_redirect.c b/tools/testing/selftests/bpf/prog_tests/tc_redirect.c
index c2426df58e172bbc7e37e489cc70ac75bbb42721..647b0a8336289b6b9eae5562d0a0ab95e65a80e1 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/tc_redirect.c
+++ b/tools/testing/selftests/bpf/prog_tests/tc_redirect.c
@@ -140,7 +140,7 @@ static 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;