On 1/11/22 19:04, Po Lu wrote:
> (lock-file "~/any/nonexistent/file/with/a/very/long/path")

Unfortunately I'm still not reproducing the problem on Fedora 35 x86-64. 
Here's how I tried to reproduce it, while in the src directory:

  valgrind --suppressions=valgrind.supp ./emacs -Q -batch -eval '
    (let ((f "/d"))
      (dotimes (i 13) (setq f (concat f f)))
      (lock-file f))
  '

I configured Emacs this way:

./configure --enable-checking

(in general this is needed if you want to use Valgrind), and used the 
attached valgrind.supp.