From owner-freebsd-current  Sun Mar 17 18:50: 5 2002
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Date: Mon, 18 Mar 2002 13:49:55 +1100 (EST)
From: Bruce Evans <bde@zeta.org.au>
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Subject: zlib breakage(was cvs commit: src/share/man/man4 ng_pptpgre.4)
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This bug affects everything that uses libz of course.  It also breaks
zgrep.  Try "cd /home/ncvs/C*/*logs; zgrep foo *".

On Sun, 17 Mar 2002, Bruce Evans wrote:

> On Sun, 17 Mar 2002, I wrote:
>
> > That may be, but ispell is not man's best friend:
> >
> >     $ man ispell
> >     Segmentation fault (core dumped)
> >
> > The bug seems to be in libz.  Upgrading to the previous version of libz
> > fixes it.
>
> The following patch (obtained from the upgrade) fixes "man ispell"
> (but may break libz).
>
> %%%
> Index: infcodes.c
> ===================================================================
> RCS file: /home/ncvs/src/lib/libz/infcodes.c,v
> retrieving revision 1.3
> diff -u -2 -r1.3 infcodes.c
> --- infcodes.c	11 Mar 2002 22:36:26 -0000	1.3
> +++ infcodes.c	17 Mar 2002 02:41:53 -0000
> @@ -201,5 +201,5 @@
>      case COPY:          /* o: copying bytes in window, waiting for space */
>        f = q - c->sub.copy.dist;
> -      while (f < s->window)             /* modulo window size-"while" instead */
> +      if (f < s->window)                /* modulo window size-"while" instead */
>          f += s->end - s->window;        /* of "if" handles invalid distances */
>        while (c->len)
> %%%
>
> The while loop caused some pointer to become invalid.  I think the bug
> is really in gcc.  The register hildng 's' seemed to get clobbered to
> (s->end - s->window) so 's' was invalid after 1 iteration.  With an
> "if" instead of a "while", gcc generates simpler code with line numbers
> that are actually correct and without the register clobber.  Compiling
> the unpatched version with -O0 also unbreaks "man ispell".
>
> Bruce

Bruce


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