Dominique wrote:
> Bram Moolenaar wrote:
>
> > I wrote:
> >
> > > Patch 8.1.0565
> > > Problem: Asan complains about reading before allocated block.
> > > Solution: Workaround: Avoid offset from becoming negative.
> > > Files: src/gui.c
> > >
> > >
> > > *** ../vim-8.1.0564/src/gui.c 2018-11-16 16:21:01.633310065 +0100
> > > --- src/gui.c 2018-12-05 19:44:07.455956642 +0100
> > > ***************
> > > *** 2753,2759 ****
> > > }
> > > else if (enc_utf8)
> > > {
> > > ! if (ScreenLines[off + col1] == 0)
> > > --col1;
> > > # ifdef FEAT_GUI_GTK
> > > if (col2 + 1 < Columns && ScreenLines[off + col2 + 1] == 0)
> > > --- 2753,2760 ----
> > > }
> > > else if (enc_utf8)
> > > {
> > > ! // FIXME: how can the first character ever be zero?
> > > ! if (col1 > 0 && ScreenLines[off + col1] == 0)
> > > --col1;
> > > # ifdef FEAT_GUI_GTK
> > > if (col2 + 1 < Columns && ScreenLines[off + col2 + 1] == 0)
> >
> > This indeed fixed the ASAN report. However, I don't see how the
> > character in the first column can be zero. That should not happen.
> >
> > The ASAN reporte started with patch 8.1.0562, which changes the parsing
> > of 'diffmode'. I don't see how that can trigger this problem. It might
> > have been caused by a library change.
> >
> > I have not been able to reproduce the problem locally. If someone can,
> > please figure out what the root cause is. E.g. would be useful to know
> > what is being redrawn and what is in the other lines. I suspect it's
> > redrawing the whole display, so perhaps it's the last line?
>
> For the record, all tests pass for me locally with
> asan too, despite trying to undo the workaround
> from patch 8.1.0565.
I suspect it's something in the setup on Travis that triggers it.
Hard to tell what it is.
I thought valgrind had a flag to check for access before allocated
memory (it normally checks for access after allocated memory), but can't
find it... Perhaps it does check both always?
--
I used to wonder about the meaning of life. But I looked it
up in the dictionary under "L" and there it was - the meaning
of life. It was less than I expected. - Dogbert
/// Bram Moolenaar -- [email protected] -- http://www.Moolenaar.net \\\
/// sponsor Vim, vote for features -- http://www.Vim.org/sponsor/ \\\
\\\ an exciting new programming language -- http://www.Zimbu.org ///
\\\ help me help AIDS victims -- http://ICCF-Holland.org ///
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