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

Fix a bunch of potentially unitialized variable usage warnings that are
reported by GCC in -O2 mode. Also silence overzealous stringop-truncation
class of warnings.

Signed-off-by: Andrii Nakryiko <[e-mail]>
Signed-off-by: Daniel Borkmann <[e-mail]>
Acked-by: Jiri Olsa <[e-mail]>
Link: https://lore.kernel.org/bpf/[e-mail]

tools/testing/selftests/bpf/Makefile

···
 BPF_GCC		?= $(shell command -v bpf-gcc;)
 SAN_CFLAGS	?=
 SAN_LDFLAGS	?= $(SAN_CFLAGS)
-CFLAGS += -g -O0 -rdynamic -Wall -Werror $(GENFLAGS) $(SAN_CFLAGS)	\
+CFLAGS += -g -O0 -rdynamic						\
+	  -Wall -Werror 						\
+	  $(GENFLAGS) $(SAN_CFLAGS)					\
 	  -I$(CURDIR) -I$(INCLUDE_DIR) -I$(GENDIR) -I$(LIBDIR)		\
 	  -I$(TOOLSINCDIR) -I$(APIDIR) -I$(OUTPUT)
 LDFLAGS += $(SAN_LDFLAGS)

tools/testing/selftests/bpf/map_tests/map_in_map_batch_ops.c

···
 {
 	int map_fd, map_index, ret;
 	__u32 map_key = 0, map_id;
-	char map_name[15];
+	char map_name[16];
 
 	for (map_index = 0; map_index < OUTER_MAP_ENTRIES; map_index++) {
 		memset(map_name, 0, sizeof(map_name));
-		sprintf(map_name, "inner_map_fd_%d", map_index);
+		snprintf(map_name, sizeof(map_name), "inner_map_fd_%d", map_index);
 		map_fd = bpf_map_create(map_type, map_name, sizeof(__u32),
 					sizeof(__u32), 1, NULL);
 		CHECK(map_fd < 0,

tools/testing/selftests/bpf/prog_tests/bloom_filter_map.c

···
 
 void test_bloom_filter_map(void)
 {
-	__u32 *rand_vals, nr_rand_vals;
-	struct bloom_filter_map *skel;
+	__u32 *rand_vals = NULL, nr_rand_vals = 0;
+	struct bloom_filter_map *skel = NULL;
 	int err;
 
 	test_fail_cases();

tools/testing/selftests/bpf/prog_tests/connect_ping.c

···
 		.sin6_family = AF_INET6,
 		.sin6_addr = IN6ADDR_LOOPBACK_INIT,
 	};
-	struct sockaddr *sa;
+	struct sockaddr *sa = NULL;
 	socklen_t sa_len;
-	int protocol;
+	int protocol = -1;
 	int sock_fd;
 
 	switch (family) {

tools/testing/selftests/bpf/prog_tests/linked_list.c

···
 
 static void list_and_rb_node_same_struct(bool refcount_field)
 {
-	int bpf_rb_node_btf_id, bpf_refcount_btf_id, foo_btf_id;
+	int bpf_rb_node_btf_id, bpf_refcount_btf_id = 0, foo_btf_id;
 	struct btf *btf;
 	int id, err;
 

tools/testing/selftests/bpf/prog_tests/lwt_helpers.h

···
 		return -1;
 
 	ifr.ifr_flags = IFF_NO_PI | (need_mac ? IFF_TAP : IFF_TUN);
-	memcpy(ifr.ifr_name, dev_name, IFNAMSIZ);
+	strncpy(ifr.ifr_name, dev_name, IFNAMSIZ - 1);
+	ifr.ifr_name[IFNAMSIZ - 1] = '\0';
 
 	err = ioctl(fd, TUNSETIFF, &ifr);
 	if (!ASSERT_OK(err, "ioctl(TUNSETIFF)")) {

tools/testing/selftests/bpf/prog_tests/queue_stack_map.c

···
 	int i, err, prog_fd, map_in_fd, map_out_fd;
 	char file[32], buf[128];
 	struct bpf_object *obj;
-	struct iphdr iph;
+	struct iphdr iph = {};
 	LIBBPF_OPTS(bpf_test_run_opts, topts,
 		.data_in = &pkt_v4,
 		.data_size_in = sizeof(pkt_v4),

tools/testing/selftests/bpf/prog_tests/sockmap_basic.c

···
 static void test_sockmap_skb_verdict_shutdown(void)
 {
 	struct epoll_event ev, events[MAX_EVENTS];
-	int n, err, map, verdict, s, c1, p1;
+	int n, err, map, verdict, s, c1 = -1, p1 = -1;
 	struct test_sockmap_pass_prog *skel;
 	int epollfd;
 	int zero = 0;
···
 static void test_sockmap_skb_verdict_fionread(bool pass_prog)
 {
 	int expected, zero = 0, sent, recvd, avail;
-	int err, map, verdict, s, c0, c1, p0, p1;
-	struct test_sockmap_pass_prog *pass;
-	struct test_sockmap_drop_prog *drop;
+	int err, map, verdict, s, c0 = -1, c1 = -1, p0 = -1, p1 = -1;
+	struct test_sockmap_pass_prog *pass = NULL;
+	struct test_sockmap_drop_prog *drop = NULL;
 	char buf[256] = "0123456789";
 
 	if (pass_prog) {

tools/testing/selftests/bpf/prog_tests/sockmap_helpers.h

···
 static inline int socket_loopback_reuseport(int family, int sotype, int progfd)
 {
 	struct sockaddr_storage addr;
-	socklen_t len;
+	socklen_t len = 0;
 	int err, s;
 
 	init_addr_loopback(family, &addr, &len);

tools/testing/selftests/bpf/prog_tests/sockmap_listen.c

···
 			      int family, int sotype, int mapfd)
 {
 	struct sockaddr_storage addr;
-	socklen_t len;
+	socklen_t len = 0;
 	u32 key = 0;
 	u64 value;
 	int err, s;
···
 
 static void redir_partial(int family, int sotype, int sock_map, int parser_map)
 {
-	int s, c0, c1, p0, p1;
+	int s, c0 = -1, c1 = -1, p0 = -1, p1 = -1;
 	int err, n, key, value;
 	char buf[] = "abc";
 

tools/testing/selftests/bpf/prog_tests/xdp_metadata.c

···
 	__u64 comp_addr;
 	void *data;
 	__u64 addr;
-	__u32 idx;
+	__u32 idx = 0;
 	int ret;
 
 	ret = recvfrom(xsk_socket__fd(xsk->socket), NULL, 0, MSG_DONTWAIT, NULL, NULL);

tools/testing/selftests/bpf/test_loader.c

···
 {
 	if (!tester->log_buf) {
 		tester->log_buf_sz = TEST_LOADER_LOG_BUF_SZ;
-		tester->log_buf = malloc(tester->log_buf_sz);
+		tester->log_buf = calloc(tester->log_buf_sz, 1);
 		if (!ASSERT_OK_PTR(tester->log_buf, "tester_log_buf"))
 			return -ENOMEM;
 	}
···
 		 bool unpriv)
 {
 	struct test_subspec *subspec = unpriv ? &spec->unpriv : &spec->priv;
-	struct bpf_program *tprog, *tprog_iter;
+	struct bpf_program *tprog = NULL, *tprog_iter;
 	struct test_spec *spec_iter;
 	struct cap_state caps = {};
 	struct bpf_object *tobj;

tools/testing/selftests/bpf/xdp_features.c

···
 static int dut_run(struct xdp_features *skel)
 {
 	int flags = XDP_FLAGS_UPDATE_IF_NOEXIST | XDP_FLAGS_DRV_MODE;
-	int state, err, *sockfd, ctrl_sockfd, echo_sockfd;
+	int state, err = 0, *sockfd, ctrl_sockfd, echo_sockfd;
 	struct sockaddr_storage ctrl_addr;
-	pthread_t dut_thread;
+	pthread_t dut_thread = 0;
 	socklen_t addrlen;
 
 	sockfd = start_reuseport_server(AF_INET6, SOCK_STREAM, NULL,

tools/testing/selftests/bpf/xdp_hw_metadata.c

···
 	struct pollfd fds[rxq + 1];
 	__u64 comp_addr;
 	__u64 addr;
-	__u32 idx;
+	__u32 idx = 0;
 	int ret;
 	int i;
 

tools/testing/selftests/bpf/xskxceiver.c

···
 	struct xsk_umem_info *umem = xsk->umem;
 	struct pollfd fds = { };
 	struct pkt *pkt;
-	u64 first_addr;
+	u64 first_addr = 0;
 	int ret;
 
 	fds.fd = xsk_socket__fd(xsk->xsk);