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

1 files changed, 1 insertions, 1 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/btf.c b/tools/testing/selftests/bpf/prog_tests/btf.c
index 8b652f5ce423..ec823561b912 100644
--- 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;