Re: librt symbol versioning breakage (was Re: Build failure, undefined reference to __mq_oshandle)

On Sun, Nov 29, 2015 at 12:27:40PM -0500, Daniel Eischen wrote:
> On Sun, 29 Nov 2015, Konstantin Belousov wrote:
> 
> > On Sun, Nov 29, 2015 at 01:23:04AM -0500, Daniel Eischen wrote:
> >> On Fri, 27 Nov 2015, Daniel Eischen wrote:
> >>
> >>> Damn, please use deischen_at_freebsd.org for replies.
> >>>
> >>> On Fri, 27 Nov 2015, Daniel Eischen wrote:
> >>>
> >>>> On Fri, 27 Nov 2015, Daniel Eischen wrote:
> >>>>
> >>>>> $ uname -a
> >>>>> FreeBSD vega 11.0-CURRENT FreeBSD 11.0-CURRENT #0 r277320: Mon Jan 19
> >>>>> 09:02:50 EST 2015
> >>>>> deischen_at_vega:/usr/FreeBSD/svn/obj/usr/FreeBSD/svn/src/sys/vega  amd64
> >>>>>
> >>>>> Upgrading to today's current, 'rm -rf /usr/obj/*; make -j8 buildworld'
> >>>>> fails here:
> >>>>>
> >>>>> ===> lib/libc/tests/gen/execve (buildconfig)
> >>>>> --- all_subdir_tests ---
> >>>>> --- all_subdir_mqueue ---
> >>>>> mqtest3.o: In function `main':
> >>>>> /usr/FreeBSD/svn/src/tests/sys/mqueue/mqtest3.c:(.text+0x139): undefined
> >>>>> reference to `__mq_oshandle'
> >>>>> /usr/FreeBSD/svn/src/tests/sys/mqueue/mqtest3.c:(.text+0x14c): undefined
> >>>>> reference to `__mq_oshandle'
> >>>>> /usr/FreeBSD/svn/src/tests/sys/mqueue/mqtest3.c:(.text+0x16c): undefined
> >>>>> reference to `__mq_oshandle'
> >>>>> /usr/FreeBSD/svn/src/tests/sys/mqueue/mqtest3.c:(.text+0x3e6): undefined
> >>>>> reference to `__mq_oshandle'
> >>>>> /usr/FreeBSD/svn/src/tests/sys/mqueue/mqtest3.c:(.text+0x3f9): undefined
> >>>>> reference to `__mq_oshandle'
> >>>>> mqtest3.o:/usr/FreeBSD/svn/src/tests/sys/mqueue/mqtest3.c:(.text+0x40f):
> >>>>> more undefined references to `__mq_oshandle' follow
> >>>>> cc: error: linker command failed with exit code 1 (use -v to see
> >>>>> invocation)
> >>>>>
> >>>>> Going to try make [-j1], next, but anyone come across this?
> >>>>
> >>>> Still fails.
> >>>>
> >>>> Why do the tests in tests/sys/mqueue/ try to use non-public APIs?
> >>
> >> So I found out that sometime in the last year or so, symbol versioning
> >> for librt was broken and leaking symbols that shouldn't have been
> >> leaked.  I've just committed a fix for this.
> >>
> >> Do a 'readelf -sw /usr/lib/librt.so.1 | grep GLOBAL | grep -v UND'
> >> and see the non FBSD_foo symbols that shouldn't be there.
> >
> > I did the following on the librt from the HEAD of about month ago:
> >
> > pooma% ls -l netboot/sandy/usr/lib/librt.so.1
> > -r--r--r--  1 root  wheel  23704 Oct 24 23:35 netboot/sandy/usr/lib/librt.so.1
> >
> > pooma% readelf -sw netboot/sandy/usr/lib/librt.so.1 | grep GLOBAL | grep -v UND | grep -v FBSDpriv | grep FBSD
> >    97: 0000000000000000     0 OBJECT  GLOBAL DEFAULT  ABS FBSD_1.0
> >
> > But I think that your commit is the good change.
> 
> 
> Can you check librt.so.1 in your buildworld temporary build
> environment?
> 
>    $ readelf -sW /usr/obj/usr/FreeBSD/svn/src/tmp/usr/lib/librt.so.1 \
>       grep -v UND | grep GLOBAL
> 
> There has to be a reason that tests/sys/mqueue/mqtest[3-4].c build
> without error when they reference __mq_oshandle.  That symbol is
> not exported from librt.
> 
> Hmm, looks like libc and libthr are also the same (leaky) in the
> temporary build environment (TBE).  So something broke when building
> the TBE libraries.
> 
> For r277320 on my system Jan 19, 2015, the TBE libraries must have
> been built correctly because mqtests[3-4] failed with unresolved
> references to __mq_oshandle.

In fact, my command was wrong.  I see that there are indeed a lot of symbols
exported which are not versioned (this is where my command was wrong, the
grep FBSD part), even for the installed librt.

Your patch fixed the issue.