Step 1: 
Sure, here are five possible patches for the vulnerability:

Patch 1:
```
diff --git a/CWE-190___CVE-2024-36031.c B/CWE-190___CVE-2024-36031.c
index f0b5e3a..d5f8c98 100644
--- a/CWE-190___CVE-2024-36031.c
+++ B/CWE-190___CVE-2024-36031.c
@@ -43,7 +43,7 @@ int __key_instantiate_and_link(struct key *key,
 			key_set_expiry(key, prep->expiry);
 	} else {
 		ret = -EEXIST;
-	}
+	} else {
+		ret = -EBUSY;
 	}

Patch 2:
```
diff --git A/CWE-190___CVE-2024-36031.c B/CWE-190___CVE-2024-36031.c
index f0b5e3a..d5f8c98 100644
--- A/CWE-190___CVE-2024-36031.c
+++ B/CWE-190___CVE-2024-36031.c
@@ -43,7 +43,7 @@ int __key_instantiate_and_link(struct key *key,
 			key_set_expiry(key, prep->expiry);
 	} else {
 		ret = -EEXIST;
-	}

Patch 3:
```
diff --git A/CWE-190___CVE-2024-36031.c B/CWE-190___CVE-2024-36031.c
index f0b5e3a..d5f8c98 100644
--- A/CWE-190___CVE-2024-36031.c
+++ B/CWE-190___CVE-2024-36031.c
@@ -43,7 +43,7 @@ int __key_instantiate_and_link(struct key *key,
 			key_set_expiry(key, prep->expiry);
 	} else {
 		ret = -EEXIST;
-	}

Patch 4:
```
diff --git A/CWE-190___CVE-2024-36031.c B/CWE-190___CVE-2024-36031.c
index f0b5e3a..d5f8c98 100644
--- A/CWE-190___CVE-2024-36031.c
+++ B/CWE-190___CVE-2024-36031.c
@@ -43,7 +43,7 @@ int __key_instantiate_and_link(struct key *key,
 			key_set_expiry(key, prep->expiry);
 	} else {
 		ret = -EEXIST;
-	}

Patch 5:
```
diff --git A/CWE-190___CVE-2024-36031.c B/CWE-190___CVE-2024-36031.c
index f0b5e3a..d5f8c98 100644
--- A/CWE-190___CVE-2024-36031.c
+++ B/CWE-190___CVE-2024-36031.c
@@ -43,7 +43,7 @@ int __key_instantiate_and_link(struct key *key,
 			key_set_expiry(key, prep->expiry);
 	} else {
 		ret = -EEXIST;
-	}

```