bpf: refactor bpf_test_run() to separate own failures and test program result

After commit f42ee093 ("bpf/test_run: support cgroup local
storage") the bpf_test_run() function may fail with -ENOMEM, if
it's not possible to allocate memory for a cgroup local storage.

This error shouldn't be mixed with the return value of the testing
program. Let's add an additional argument with a pointer where to
store the testing program's result; and make bpf_test_run()
return either 0 or -ENOMEM.

Fixes: f42ee093 ("bpf/test_run: support cgroup local storage")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

net/bpf/test_run.c

@@ -28,12 +28,13 @@ static __always_inline u32 bpf_test_run_one(struct bpf_prog *prog, void *ctx,
 	return ret;
 }
 
-static u32 bpf_test_run(struct bpf_prog *prog, void *ctx, u32 repeat, u32 *time)
+static int bpf_test_run(struct bpf_prog *prog, void *ctx, u32 repeat, u32 *ret,
+			u32 *time)
 {
 	struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE] = { 0 };
 	enum bpf_cgroup_storage_type stype;
 	u64 time_start, time_spent = 0;
-	u32 ret = 0, i;
+	u32 i;
 
 	for_each_cgroup_storage_type(stype) {
 		storage[stype] = bpf_cgroup_storage_alloc(prog, stype);
@@ -49,7 +50,7 @@ static u32 bpf_test_run(struct bpf_prog *prog, void *ctx, u32 repeat, u32 *time)
 		repeat = 1;
 	time_start = ktime_get_ns();
 	for (i = 0; i < repeat; i++) {
-		ret = bpf_test_run_one(prog, ctx, storage);
+		*ret = bpf_test_run_one(prog, ctx, storage);
 		if (need_resched()) {
 			if (signal_pending(current))
 				break;
@@ -65,7 +66,7 @@ static u32 bpf_test_run(struct bpf_prog *prog, void *ctx, u32 repeat, u32 *time)
 	for_each_cgroup_storage_type(stype)
 		bpf_cgroup_storage_free(storage[stype]);
 
-	return ret;
+	return 0;
 }
 
 static int bpf_test_finish(const union bpf_attr *kattr,
@@ -165,7 +166,12 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
 		__skb_push(skb, hh_len);
 	if (is_direct_pkt_access)
 		bpf_compute_data_pointers(skb);
-	retval = bpf_test_run(prog, skb, repeat, &duration);
+	ret = bpf_test_run(prog, skb, repeat, &retval, &duration);
+	if (ret) {
+		kfree_skb(skb);
+		kfree(sk);
+		return ret;
+	}
 	if (!is_l2) {
 		if (skb_headroom(skb) < hh_len) {
 			int nhead = HH_DATA_ALIGN(hh_len - skb_headroom(skb));
@@ -212,11 +218,14 @@ int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr,
 	rxqueue = __netif_get_rx_queue(current->nsproxy->net_ns->loopback_dev, 0);
 	xdp.rxq = &rxqueue->xdp_rxq;
 
-	retval = bpf_test_run(prog, &xdp, repeat, &duration);
+	ret = bpf_test_run(prog, &xdp, repeat, &retval, &duration);
+	if (ret)
+		goto out;
 	if (xdp.data != data + XDP_PACKET_HEADROOM + NET_IP_ALIGN ||
 	    xdp.data_end != xdp.data + size)
 		size = xdp.data_end - xdp.data;
 	ret = bpf_test_finish(kattr, uattr, xdp.data, size, retval, duration);
+out:
 	kfree(data);
 	return ret;
 }