Not a bug: you are seeing these messages because you turned on the "Verbose
Diagnostics" checkbox on the "Advanced" tab of the screensaver control panel.

Run "xscreensaver-demo" and un-check that box again.

I have never run xscreensaver-demo before in my life.  I just ran it now and
confirmed that the "Verbose Dialognostics" [sic] box on the Advanced tab is
*not* checked.

Well, I promise you, the verbose flag is on or you wouldn't be getting these
messages.  Did you launch xscreensaver with -v?  Is verbose set to true in your
~/.xscreensaver file or in the app-defaults file?

No -v.  No .xscreensaver file.  No verbose xscreensaver setting in my X
resources.  I've changed nothing in my xscreensaver configuration or how I
invoke it, and yet these messages have started appearing when they were not
appearing before.

Perhaps the RPM is compiled in a way which causes these messages to appear when
they wouldn't normally.

Please do me a favor and stop treating me like an idiot (I don't know if that
was your intent, but it sure feels that way).  Take a look at how many bugs I've
filed in bugzilla.  I know a thing or two about reporting bugs.

Not to mention the fact that the first "xscreensaver" was written by me before
you even thought about writing yours :-).

I'm not treating you like an idiot.  I'm telling you that I have no idea why you
are experiencing the things you are, and pointing out the only things that I can
think of that could be causing it.  If you're taking that personally, I can't do
anything about that...

Has this ever reappeared? I can't reproduce it here.

I can't make it happen now, but I'm pretty certain I've seen the messages on my
xscreensaver window recently.  I also see this in my .xsession-errors file,
which suggests that xscreensaver is sending it to stderr, and it shouldn't be:

xscreensaver: 23:04:06: PAM: brk grew by 40K.
xscreensaver: 23:04:09: PAM: brk grew by 8K.

I just checked my settings with xscreensaver-demo, and I don't have any verbose
settings of any sort enabled.  I'm using xscreensaver-4.07-2.  Here are my
xscreensaver resources:

XScreenSaver*lock:      True
XScreenSaver*splash:    False
XScreenSaver*dpmsEnabled:       True
XScreenSaver*programs:

xscreensaver does normally send that message to stderr. It implies a leak somewhere.

normally, meaning 'to stderr' as opposed 'to the screen'.

I can't reproduce this.  Johnathan, if it happens to you again, can
you please reopen the bug?

To reproduce it, try locking the screen, and then entering a wrong
password to unlock the screen.

Just a "metoo" here. This *does* happen, just not reproducibly.

I came home to my system (FC2) today to see that exact message. Is
there a possibility that when drawing on a root window, that STDERR is
redirected to the screen somehow?

FWIW, I just experienced this exact problem with xscreensaver-4.18-4 on Fedora
Core 3. Screen is set to blank, verbose is disabled. However it did not result
from an invalid password attempt. I merely left my office for 2 minutes and it's
extremely unlikely that anyone tried to log onto my computer while I was out.

(In reply to Jonathan Kamens from comment #0)
> xscreensaver-4.05-1 from rawhide.
> 
> I've got xscreensver configured to just blank the screen.  When I go to
> unlock,
> I see messages written in yellow in the upper corner of the screen like
> ("PAM:
> brk increased by 40K" and "xscreensaver: child process X exited with SIGTERM"
> (or something like that).  These are probably debugging messages that need
> to go
> away.

In the ~/.xscreensaver file, set "captureStderr:" to "False".

XScreenSaver 5.45 on Debian 11 here