Unsound usages of VecFromRawParts

[llooFlashooll]

Hi, I am scanning the lever in the latest version with my own static analyzer tool.

Unsafe conversion found at: src/alloc/mod.rs#L13

pub(crate) fn bucket_allocate_cont<T>(buckets: usize) -> Result<Vec<T>> {
    // debug_assert!((buckets != 0) && ((buckets & (buckets - 1)) == 0), "Capacity should be power of 2");

    // Array of buckets
    let data = Layout::array::<T>(buckets)?;

    unsafe {
        let p = std::alloc::alloc_zeroed(data);

        Ok(Vec::<T>::from_raw_parts(p as *mut T, 0, buckets))
    }
}

This unsound implementation of Vec::from_raw_parts would create a dangling pointer issues if the p is dropped automatically. The 'mem::forget' function can be used to avoid the issue.

This would potentially cause undefined behaviors in Rust. If we further manipulate the problematic converted types, it would potentially lead to different consequences such as uaf or double free. I am reporting this issue for your attention.