diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index f2bce62f79595434fd03d07a89bb482def33076d..cadf65818c8c32fdcf8c78e9cd583c2be411c7d8 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -521,6 +521,7 @@ BPF_CALL_4(bpf_strtol, const char *, buf, size_t, buf_len, u64, flags,
 	long long _res;
 	int err;
 
+	*res = 0;
 	err = __bpf_strtoll(buf, buf_len, flags, &_res);
 	if (err < 0)
 		return err;
@@ -547,6 +548,7 @@ BPF_CALL_4(bpf_strtoul, const char *, buf, size_t, buf_len, u64, flags,
 	bool is_negative;
 	int err;
 
+	*res = 0;
 	err = __bpf_strtoull(buf, buf_len, flags, &_res, &is_negative);
 	if (err < 0)
 		return err;
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 086dab9c427c18586283f425957a8978e4e7ed3f..476301afe89c7292df267ff8ecb32c0c911248d8 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -5688,6 +5688,7 @@ static const struct bpf_func_proto bpf_sys_close_proto = {
 
 BPF_CALL_4(bpf_kallsyms_lookup_name, const char *, name, int, name_sz, int, flags, u64 *, res)
 {
+	*res = 0;
 	if (flags)
 		return -EINVAL;
 
diff --git a/net/core/filter.c b/net/core/filter.c
index f75e5f168eff1a15346d49c02101b38ce09fcfd3..b0fbc25026e26b69f01d4785e11bb3baa707d8d6 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -6290,20 +6290,25 @@ BPF_CALL_5(bpf_skb_check_mtu, struct sk_buff *, skb,
 	int ret = BPF_MTU_CHK_RET_FRAG_NEEDED;
 	struct net_device *dev = skb->dev;
 	int skb_len, dev_len;
-	int mtu;
+	int mtu = 0;
 
-	if (unlikely(flags & ~(BPF_MTU_CHK_SEGS)))
-		return -EINVAL;
+	if (unlikely(flags & ~(BPF_MTU_CHK_SEGS))) {
+		ret = -EINVAL;
+		goto out;
+	}
 
-	if (unlikely(flags & BPF_MTU_CHK_SEGS && (len_diff || *mtu_len)))
-		return -EINVAL;
+	if (unlikely(flags & BPF_MTU_CHK_SEGS && (len_diff || *mtu_len))) {
+		ret = -EINVAL;
+		goto out;
+	}
 
 	dev = __dev_via_ifindex(dev, ifindex);
-	if (unlikely(!dev))
-		return -ENODEV;
+	if (unlikely(!dev)) {
+		ret = -ENODEV;
+		goto out;
+	}
 
 	mtu = READ_ONCE(dev->mtu);
-
 	dev_len = mtu + dev->hard_header_len;
 
 	/* If set use *mtu_len as input, L3 as iph->tot_len (like fib_lookup) */
@@ -6321,15 +6326,12 @@ BPF_CALL_5(bpf_skb_check_mtu, struct sk_buff *, skb,
 	 */
 	if (skb_is_gso(skb)) {
 		ret = BPF_MTU_CHK_RET_SUCCESS;
-
 		if (flags & BPF_MTU_CHK_SEGS &&
 		    !skb_gso_validate_network_len(skb, mtu))
 			ret = BPF_MTU_CHK_RET_SEGS_TOOBIG;
 	}
 out:
-	/* BPF verifier guarantees valid pointer */
 	*mtu_len = mtu;
-
 	return ret;
 }
 
@@ -6339,19 +6341,21 @@ BPF_CALL_5(bpf_xdp_check_mtu, struct xdp_buff *, xdp,
 	struct net_device *dev = xdp->rxq->dev;
 	int xdp_len = xdp->data_end - xdp->data;
 	int ret = BPF_MTU_CHK_RET_SUCCESS;
-	int mtu, dev_len;
+	int mtu = 0, dev_len;
 
 	/* XDP variant doesn't support multi-buffer segment check (yet) */
-	if (unlikely(flags))
-		return -EINVAL;
+	if (unlikely(flags)) {
+		ret = -EINVAL;
+		goto out;
+	}
 
 	dev = __dev_via_ifindex(dev, ifindex);
-	if (unlikely(!dev))
-		return -ENODEV;
+	if (unlikely(!dev)) {
+		ret = -ENODEV;
+		goto out;
+	}
 
 	mtu = READ_ONCE(dev->mtu);
-
-	/* Add L2-header as dev MTU is L3 size */
 	dev_len = mtu + dev->hard_header_len;
 
 	/* Use *mtu_len as input, L3 as iph->tot_len (like fib_lookup) */
@@ -6361,10 +6365,8 @@ BPF_CALL_5(bpf_xdp_check_mtu, struct xdp_buff *, xdp,
 	xdp_len += len_diff; /* minus result pass check */
 	if (xdp_len > dev_len)
 		ret = BPF_MTU_CHK_RET_FRAG_NEEDED;
-
-	/* BPF verifier guarantees valid pointer */
+out:
 	*mtu_len = mtu;
-
 	return ret;
 }