Am Fri, 13 Oct 2017 09:13:27 +0200 schrieb Norbert Lange <[email protected]>:
> Hello, > > I tracked down the source of information to this: > https://wiki.ubuntu.com/SecurityTeam/PIE Ok here they suggest to invoke gcc with "-r", which seems to be a hidden undocumemted feature. > I changed the flags from "-Wl,-Ur" to "-Wl,-U -r", so you wont get an This passes "-r" to gcc and an invalid "-U" to ld. How about "-Wl,-Ur -r" that would give the -r to ld and keep the c++ semantics. > explanation from me, why -U has to be passed for the linker. > And by the way, gcc accepts -U aswell, so this might be preferable to > be used directly too. "-U" in gcc seems to be for the preprocessor. To me that seems to be something very different. > I don`t know why those flags aren' t documented, bug in gcc > documentation? As far as I understand is that gcc is smart enough to > correctly deal with the flags gcc directly received, but the linker > lacks that information. > > I don' t know what the issue is with the C++ Constructors, in the > context of this change? I do not know whether there is an issue. But we have "-Ur" as ldflag in there and your patch removes it. > (I heard about the issues if those reside in a shared library, use > function from libcobald and don't depend on libcobald. Which is more > of a broken build to me if you don't add the depended libs, and will > bite you the same way if you use GCCs constructor attribute) > > Kind regards, > Norbert. > > 2017-10-12 10:33 GMT+02:00 Henning Schild > <[email protected]>: > > Hey Norbert, > > > > thanks for looking into that again! Could you please explain how and > > why that works, or point out what to look at in flint? Mailing list > > thread, commit, something like that. > > > > As far as i can see gcc now gets a "-r" which i do not find in the > > manpage. And ld gets a "-U" which i do not find in its manpage. And > > there is something about c++ constructors which might change the > > behaviour of xenomai. > > > > Henning > > > > Am Tue, 10 Oct 2017 16:38:50 +0200 > > schrieb Norbert Lange <[email protected]>: > > > >> Some highly trivial fix attached! > >> Its strange that this flag is not documented in the manual (I found > >> out abaout this fix from > >> https://launchpad.net/ubuntu/+source/flint) > >> > >> Norbert Lange > >> > >> 2017-08-10 11:49 GMT+02:00 Henning Schild > >> <[email protected]>: > >> > Hi Norbert, > >> > > >> > Thanks! In fact that issue has come up before and a similar > >> > workaround was described. It should be fixed, patches welcome! > >> > > >> > Henning > >> > > >> > Am Wed, 9 Aug 2017 16:21:02 +0200 > >> > schrieb Norbert Lange <[email protected]>: > >> > > >> >> Hello, > >> >> > >> >> Building the xenomai package won`t work because debian now > >> >> defaults to using pie, and the linker will complain with "ld: -r > >> >> and -pie may not be used together" > >> >> > >> >> A workaround for now is to add the flags manually: > >> >> ../xenomai-3.0.5/configure LDFLAGS=-no-pie CFLAGS="-fno-PIE > >> >> -fno-pie -no-pie" > >> >> > >> >> A real fix would be similar to > >> >> http://lists.gnu.org/archive/html/bug-grub/2016-11/msg00011.html > >> >> (no-pie is not supported on old and other compilers) > >> >> > >> >> Kind regards, > >> >> Norbert > >> >> > >> >> _______________________________________________ > >> >> Xenomai mailing list > >> >> [email protected] > >> >> https://xenomai.org/mailman/listinfo/xenomai > >> > > > _______________________________________________ Xenomai mailing list [email protected] https://xenomai.org/mailman/listinfo/xenomai
