[vorbis] Short block test

[Nils Philippsen]

On Fri, 22 Dec 2000, Segher Boessenkool wrote:

>
>
> Nils Philippsen wrote:
> >
> > On Thu, 21 Dec 2000, Monty wrote:
> >
> > > > > I couldn't use mode -b 350 because oggenc always hangs at 98% with
> > > > > this clip and the file produced has annoying distorsions...
> > >
> > > Ahhhh!  Someone else reported this bug and I could not reproduce it.
> > > Is this with Frank's test sample?  Windows oggenc or unix?  If I can
> > > get things to hang on Linux where I can watch it, I'll be very happy.
> >
> > I can reproduce it here:
> >
> > - libogg, libvorbis, vorbis-tools from CVS 20001220
> > - Red Hat Linux 7/IA32 (heavily updated)
> > - glibc-2.2
> > - kernel 2.4.0-test12 (if that matters, it shouldn't)
> >
> > It runs fine until 98.3% where it hangs -- apparently in an endless loop
> > because I can't strace any system calls being executed. The resulting ogg
> > file has some really nasty artifacts...
>
> Can you compile it without math function inlining, and then ltrace it? That
> would be very slow, of course, but would tell us about where the bug is
> (if we're a bit lucky).
>
> Or connect to the running encoder with gdb, and get a backtrace.

Okie:

#0  0x40038f1f in Newton_Raphson_Maehly () from /usr/lib/libvorbis.so.0
#1  0x40039159 in vorbis_lpc_to_lsp () from /usr/lib/libvorbis.so.0
#2  0x4003e02e in floor0_forward () from /usr/lib/libvorbis.so.0
#3  0x4003fe28 in mapping0_forward () from /usr/lib/libvorbis.so.0
#4  0x4003963c in vorbis_analysis () from /usr/lib/libvorbis.so.0
#5  0x804a870 in strcpy () at ../sysdeps/generic/strcpy.c:31
#6  0x80497a5 in strcpy () at ../sysdeps/generic/strcpy.c:31
#7  0x400cbfd1 in __libc_start_main (main=0x8049140 <strcpy+280>, argc=4,
    ubp_av=0xbffff83c, init=0x8048cf0 <_init>, fini=0x804ae2c <_fini>,
    rtld_fini=0x4000e254 <_dl_fini>, stack_end=0xbffff834)
    at ../sysdeps/generic/libc-start.c:118

This is against the original libs, if I compile libvorbis as you suggested
(with -fno-inline or make debug), it doesn't show this error, so this
might as well be a compiler bug regarding inlined functions. I run
gcc-2.96-69 (AKA "the compiler that spoilt world peace" :-)) for that
matter. If you like, I can file a bugzilla ticket.

Nils

-- 
         Nils Philippsen / +49.711.96437.250 / nils at redhat.de
       Red Hat GmbH / Hauptstätter Straße 58 / D70178 Stuttgart
The use of COBOL cripples the mind; its teaching should, therefore, be
regarded as a criminal offence.                  -- Edsger W. Dijkstra

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