Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

erofs: unify lcn as u64 for 32-bit platforms

As sashiko reported [1], `lcn` was typed as `unsigned long` (or `unsigned int` sometimes), which is only 32 bits wide on 32-bit platforms, which causes `(lcn << lclusterbits)` to be truncated at 4 GiB.

In order to consolidate the logic, just use `u64` consistently around the codebase.

[1] https://sashiko.dev/r/20260420034612.1899973-1-hsiangkao%40linux.alibaba.com