To generate the patch for the given code slice with a CWE-787 (Out-of-bounds Write) vulnerability, we can follow these reasoning steps:

### Step 1: Root Cause Analysis

- 1: Validate Memory Allocation:
  - The code allocates memory for a `struct resource` using `kmalloc`.
  - `kmalloc` does not initialize the allocated memory, which means it may contain arbitrary values.

- 2: Potential Vulnerability:
  - If the allocated memory is not initialized and is used without proper initialization, it can lead to undefined behavior.
  - In the context of CWE-787, this can result in writing to memory locations outside the bounds of the allocated buffer if the uninitialized memory contains values that are interpreted as indices or pointers.

- 3: Vulnerability in the Given Code:
  - The vulnerability arises because the allocated memory for `struct resource` is not initialized.
  - Although the code does not explicitly show the usage of the allocated memory, it is likely that the `struct resource` will be used to store or access memory locations, which can lead to out-of-bounds writes if the memory is not properly initialized.

### Conclusion:
The vulnerable behavior in this code is due to the lack of initialization of the allocated memory for `struct resource`. This can lead to undefined behavior and potentially out-of-bounds writes if the uninitialized memory is used to access or store data.

### Step 2: Fixing Strategy

- A common fixing strategy for this type of vulnerability is to ensure that the allocated memory is properly initialized.
- In the Linux kernel, `kzalloc` is a function that allocates memory and initializes it to zero.
- By using `kzalloc` instead of `kmalloc`, we can ensure that the allocated memory for `struct resource` is properly initialized, preventing potential out-of-bounds writes.

Therefore, the patch should be:
```
<         struct resource *rp = kmalloc(sizeof(*rp), GFP_KERNEL);
---
>         struct resource *rp = kzalloc(sizeof(*rp), GFP_KERNEL);
```
This change ensures that the allocated memory is initialized to zero, preventing the CWE-787 vulnerability.