Re: fix for libpthread

On Wed, 3 Mar 2004, Alfred Perlstein wrote:

> * Alfred Perlstein <alfred_at_freebsd.org> [040303 02:46] wrote:
> > * David Xu <davidxu_at_freebsd.org> [040303 00:09] wrote:
> > > Alfred Perlstein wrote:
> > > 
> > > >This assertion doesn't seem necessary.  Apply to 
> > > >src/lib/libpthread/thread/thr_spinlock.c
> > > >
> > > As I saw some reports in the -CURRENT list,  the panic is always 
> > > triggered by mix up
> > > of libc_r and libpthread in same program. So to avoid other mysterious 
> > > crashes,
> > > I'd like keep the code there, it is now used to check the problem.
> > 
> > Can you clarify?  Without this patch mplayer refuses to work for
> > me and crashes at startup.  With the patch it runs just fine.
> > 
> > Is there a workaround?
> 
> I sort of see what you are saying:
> ~ % ldd `which mplayer`
> /usr/local/bin/mplayer:
>         libpng.so.5 => /usr/local/lib/libpng.so.5 (0x2828e000)
>         libz.so.2 => /lib/libz.so.2 (0x282b0000)
>         libfreetype.so.9 => /usr/local/lib/libfreetype.so.9 (0x282bd000)
>         libncurses.so.5 => /lib/libncurses.so.5 (0x28320000)
>         libGL.so.1 => /usr/X11R6/lib/libGL.so.1 (0x2835c000)
>         libXv.so.1 => /usr/X11R6/lib/libXv.so.1 (0x283c9000)
>         libXext.so.6 => /usr/X11R6/lib/libXext.so.6 (0x283ce000)
>         libX11.so.6 => /usr/X11R6/lib/libX11.so.6 (0x283dd000)
>         libpthread.so.1 => /usr/lib/libpthread.so.1 (0x284a5000)
>         libiconv.so.3 => /usr/local/lib/libiconv.so.3 (0x284c8000)
>         libintl.so.6 => /usr/local/lib/libintl.so.6 (0x285b7000)
>         libm.so.2 => /lib/libm.so.2 (0x285bf000)
>         libc.so.5 => /lib/libc.so.5 (0x285d7000)
>         libc_r.so.5 => /usr/lib/libc_r.so.5 (0x286a2000)
> 
> I see somehow it got linked against BOTH libpthread and libc_r,
> there has to be a way to prevent that sort of bogus linkage
> from happening. :(  Or at least make it work right when it
> does happen...

It's too hard to make it work correctly; it involves coordinating
some of the thread library internals which are private.  If someone
linked against both LinuxThreads or NPT and libpthread, would
you advocate fixing libc/libc_r/libthr/libpthread to allow this? :-)

-- 
Dan Eischen