CVE-2026-31514

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

erofs: set fileio bio failed in short read case

For file-backed mount, IO requests are handled by vfs_iocb_iter_read().
However, it can be interrupted by SIGKILL, returning the number of
bytes actually copied. Unused folios in bio are unexpectedly marked
as uptodate.

  vfs_read
    filemap_read
      filemap_get_pages
        filemap_readahead
          erofs_fileio_readahead
            erofs_fileio_rq_submit
              vfs_iocb_iter_read
                filemap_read
                  filemap_get_pages  <= detect signal
              erofs_fileio_ki_complete  <= set all folios uptodate

This patch addresses this by setting short read bio with an error
directly.