xless 1.7 -- segmentation fault in libXaw using search dialog popup

[J G Miller]

PRETTY_NAME="Ubuntu quantal (12.10)"
VERSION="12.10, Quantal Quetzal"

Package: xless
Priority: optional
Section: universe/text
Installed-Size: 128
Origin: Ubuntu
Maintainer: Ubuntu Developers <email address hidden>
Bugs: https://bugs.launchpad.net/ubuntu/+filebug
Architecture: i386
Version: 1.7-14.1
Depends: libc6 (>= 2.4), libx11-6, libxaw7, libxmu6, libxt6
Filename: pool/universe/x/xless/xless_1.7-14.1_i386.deb

xless has a button to popup a search dialog window. After entering the search string and hitting <CR>, the application crashes with a segmentation violation. Using the search dialog invoked with <CTRL><S> also results in a crash, so I get the impression that the search is successful and that the crash occurs when redrawing the text display pane to show the string highlighted.

This bug was not present as far as I am aware in previous versions of Ubuntu and appeared with the change in version of libXaw (as well as the related upgrade of libXt of course).

After downloading the source and using debian/rules to compile with -g flag and dh_strip commented out, and installing the debug packages

ii libx11-6-dbg:i386 2:1.5.0-1ubuntu0.1 i386 X11 client-side library (debug package)
ii libxaw7-dbg:i386 2:1.0.10-2 i386 X11 Athena Widget library (debug package)
ii libxt6-dbg:i386 1:1.1.3-1ubuntu0.12.10 i386 X11 toolkit intrinsics library (debug package)

the attached backtrace report was generated indicating the cause of the crash occurs in XawTextSelectionList of libXaw, so perhaps the bug should be filed against libXaw rather than xless.

As I use xless as my manual page viewer, I find this bug to be extremely inconvenient.

[J G Miller (jgmiller)]

A patch was submitted to the Debian BTS concerning a similar type of bug in xcolorsel.

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=785307

which when applied to xcolorsel source stops xcolorsel from crashing. The patch is a one line
call to XawTextSetSelection to effectively "initialize" the starting position to 0.

If a similar patch is added to callbacks.c at line 269 to initialize the starting position to 0
(with the end position set also 0 to avoid annoyingly highlighting the text in the document pane from the zero position to say the calculated "beg" or "end" position, with the now second call of XawTextSetSelection doing the actual highlighting of the found string)

+ XawTextSetSelection(wi->text, 0, 0)

the crash in XawTextSetSelection to go to the actual position of the found string no longer occurs,thus curing the bug.