Comment 23 for bug 1885403

Before the really interesting bit first some data that is equal.

Frame/Backtrace wise in gdb they do not look too different:

Debian:
Breakpoint 1, tls_log_mask (log_param=0x55555555c6f8 "-L option", log_level=0x5555555728c0 "routine,certmatch") at tls_misc.c:545
545 tls_misc.c: No such file or directory.
(gdb) bt
#0 tls_log_mask (log_param=0x55555555c6f8 "-L option", log_level=0x5555555728c0 "routine,certmatch") at tls_misc.c:545
#1 0x00005555555587d2 in ?? ()
#2 0x00007ffff79c3565 in __libc_start_main (main=0x5555555580f0, argc=2, argv=0x7fffffffe6b8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>,
    stack_end=0x7fffffffe6a8) at ../csu/libc-start.c:332
#3 0x0000555555559bae in ?? ()

Ubuntu:
Breakpoint 1, tls_log_mask (log_param=0x55555555c6f8 "-L option", log_level=0x5555555728c0 "routine,certmatch") at /build/postfix-9Thbkc/postfix-3.5.6/src/tls/tls_misc.c:545
545 /build/postfix-9Thbkc/postfix-3.5.6/src/tls/tls_misc.c: No such file or directory.
(gdb) bt
#0 tls_log_mask (log_param=0x55555555c6f8 "-L option", log_level=0x5555555728c0 "routine,certmatch") at /build/postfix-9Thbkc/postfix-3.5.6/src/tls/tls_misc.c:545
#1 0x00005555555587d2 in ?? ()
#2 0x00007ffff79c2565 in __libc_start_main (main=0x5555555580f0, argc=2, argv=0x7fffffffe6b8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>,
    stack_end=0x7fffffffe6a8) at ../csu/libc-start.c:332
#3 0x0000555555559bae in ?? ()

And ldd for both is the same:
$ ldd /usr/sbin/posttls-finger | grep tls
    libpostfix-tls.so => /usr/lib/postfix/libpostfix-tls.so (0x00007f78aeba1000)

The file is loaded and mapped in both cases - both look like:
$ cat /proc/$(pidof posttls-finger)/maps | grep tls.so
7ffff7f97000-7ffff7fa0000 r--p 00000000 00:ba 86770 /usr/lib/postfix/libpostfix-tls.so
7ffff7fa0000-7ffff7fb8000 r-xp 00009000 00:ba 86770 /usr/lib/postfix/libpostfix-tls.so
7ffff7fb8000-7ffff7fbf000 r--p 00021000 00:ba 86770 /usr/lib/postfix/libpostfix-tls.so
7ffff7fbf000-7ffff7fc1000 r--p 00027000 00:ba 86770 /usr/lib/postfix/libpostfix-tls.so
7ffff7fc1000-7ffff7fc2000 rw-p 00029000 00:ba 86770 /usr/lib/postfix/libpostfix-tls.so

Both have the same symbols (slight differences due to LTO, but not everywhere)
root@i-postfix:~# nm libpostfix-tls.so.debugubuntu | grep ' [tT].*tls_log_mask'
000000000000d3e4 T tls_log_mask
root@i-postfix:~# nm libpostfix-tls.so.debugdebian | grep ' [tT].*tls_log_mask'
000000000000c470 T tls_log_mask