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

From: Konstantin Belousov <kostikbel_at_gmail.com>
Date: Mon, 30 Nov 2015 16:55:18 +0200
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.
Received on Mon Nov 30 2015 - 13:55:24 UTC

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