bug#53136: 28.0.90; segfault in lock_file

[Po Lu]

Eli Zaretskii <eliz@gnu.org> writes:

> So we somehow wrote more than 8192 bytes by that memcpy line?  I find
> this hard to believe.

Manual inspection of the core dump seems to reveal something very
different from what the debugger said (and I asked for a second opinion
on this as well):

 - lock_info.dot and lock_info.colon are NULL.
 - lock_filename is a Lisp string, the data is
   "/home/oldosfan/Mail/archive/sent/2022-01".
 - handler, subject_buf are NULL
 - dot is NULL
 - pidlen is -1 (long int)
 - replacementlen is 6

Any ideas?  Thanks.