Re: To bust or not to bust: the C/C++ code freeze for a (poor man's) fuzzer-provoked SEGV

"G. Branden Robinson" <[email protected]> Wed, 28 Jan 2026 18:23:43 -0600

Newsgroups	gmane.comp.printing.groff.general
Message-ID	<20260129002343.4gtop2odlh5wb5xv@illithid>

At 2026-01-28T23:03:28+0000, Deri wrote:
> I only discovered it when doing the research for the pdf attached to
> <https:// savannah.gnu.org/bugs/?67544#comment8>. I wanted to attach a
> .png at the top of the page:-
> 
> .LP
> \X'pdf: pdfpic ne-pic.png -L \n[LL]z'
> .sp 1.4c
> .NH 1 ghostscript
> Ghostscript
> 
> It only avoided the SIGSEGV if I added a .LP before it.

Insofar as you had to issue an `LP` call before populating your ms(7)
document with content, then it's not a bug that you got an undesirable
outcome when you omitted it.

groff_ms(7):
Document structure
     The ms macro package expects a certain amount of structure: a well‐
     formed document contains at least one paragraphing or heading macro
     call.  To compose a simple document from scratch, begin it by
     calling LP or PP.  ...

$ eqn -Tutf8 ./build/doc/ms.ms | nroff -rLL=80n -pt -ms | sed -n '43,46p'
1.1.  Basic information

Prepare  an ms document with your preferred text editor.  Call an ms macro early
in the document to initialize the package.  A macro is a formatting  instruction
...

"Typing Documents on the Unix System: Using the -ms macros with Troff
and Nroff", M.E. Lesk, 13 November 1978:

    Warning: You can't just begin a document with a line of text.  Some
    -ms command must precede any text input.

However, a core dump should not be GNU troff's means of informing you
that you erred.

I'll test my excessively advanced input stream pointer hypothesis
presently.

Regards,
Branden

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