With commit 16f196874 (kern/file: Implement filesystem reference
counting) files hold a reference to their file systems.
When closing a file in grub_file_close() we should not expect
file->fs to stay valid after calling grub_dl_unref() on file->fs->mod.
So, grub_dl_unref() should be called after file->fs->fs_close().
Fixes: CVE-2025-54771
Fixes: 16f196874 (kern/file: Implement filesystem reference counting)
Reported-by: Thomas Frauendorfer | Miray Software <tf@miray.de>
Signed-off-by: Thomas Frauendorfer | Miray Software <tf@miray.de>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>