Here are five possible code completions for the `thermal_debug_cdev_remove` function, addressing the CWE-476 (NULL Pointer Dereference) vulnerability:

1. Basic NULL check:
```c
void thermal_debug_cdev_remove(struct thermal_cooling_device *cdev)
{
    if (cdev == NULL) {
        pr_err("Error: NULL cooling device pointer\n");
        return;
    }
    
    // Proceed with removal logic
    // ...
}
```

2. Using assert macro:
```c
#include <assert.h>

void thermal_debug_cdev_remove(struct thermal_cooling_device *cdev)
{
    assert(cdev != NULL);
    
    // Proceed with removal logic
    // ...
}
```

3. Logging and early return:
```c
void thermal_debug_cdev_remove(struct thermal_cooling_device *cdev)
{
    if (!cdev) {
        pr_warn("Attempted to remove NULL cooling device\n");
        return;
    }
    
    // Proceed with removal logic
    // ...
}
```

4. Using a macro for NULL check:
```c
#define CHECK_NULL_AND_RETURN(ptr) \
    do { \
        if ((ptr) == NULL) { \
            pr_err("%s: NULL pointer\n", __func__); \
            return; \
        } \
    } while (0)

void thermal_debug_cdev_remove(struct thermal_cooling_device *cdev)
{
    CHECK_NULL_AND_RETURN(cdev);
    
    // Proceed with removal logic
    // ...
}
```

5. Detailed error reporting:
```c
#include <errno.h>

void thermal_debug_cdev_remove(struct thermal_cooling_device *cdev)
{
    if (cdev == NULL) {
        pr_err("thermal_debug_cdev_remove: Invalid argument (cdev is NULL)\n");
        errno = EINVAL;
        return;
    }
    
    // Proceed with removal logic
    // ...
}
```

Each of these completions addresses the CWE-476 vulnerability by checking for NULL pointers before proceeding with the removal logic. The choice between them depends on the specific requirements of your project, such as error handling conventions, logging preferences, and code style guidelines.