I've got a puzzling build failure today and could use some direction on what to do. The build is here: https://koji.fedoraproject.org/koji/taskinfo?taskID=9204498. The cddlib package can be built both with and without GMP support. Most applications can work with either version, so we want to build them against a GMP-enabled cddlib, for efficiency. However, polymake wants to link against both GMP-enabled and GMP-disabled versions of cddlib. To support this, without using polymake's bundled version of cddlib, we long ago built both versions of the library, named libcdd.so.0.0.0 and libcddgmp.so.0.0.0. Since they contain identical symbols, the bundled polylmake version renames all of the symbols in the GMP-enabled version to have "_gmp" suffixes. We did likewise, but to support applications that only want the GMP-enabled version and expect the original unaltered symbol names, we made declarations of the form "foo __attribute__((alias(foo_gmp)))" for each external symbol foo. That lets polymake link with both versions as it expects, and other applications don't have to be modified to use the new symbol names. Now, cddlib was rebuilt just before alpha freeze, so it has been built with the hardening flags. This morning, I tried to rebuild gfan after adding in $RPM_LD_FLAGS, so that it too would be built hardened. The link step fails on x86_64 with this message: /bin/ld: ./lp_cdd.o: relocation R_X86_64_PC32 against undefined symbol `dd_purezero' can not be used when making a shared object; recompile with -fPIC /bin/ld: final link failed: Bad value collect2: error: ld returned 1 exit status I am puzzled by this. First, the link is attempting to create a binary, not a shared object. Second, every object in cddlib was built with -fPIC. Every object in gfan was built with -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1, which should make them be built with -fpie, right? I also tried building gfan with -fPIE, but that didn't help. Third, removing -specs=/usr/lib/rpm/redhat/redhat-hardened-ld from the link line results in a successful link. Fourth, examining libcddgmp.so.0.0.0 (the cddlib library in question) with readelf shows this in the relocation section: 000000244f90 027a00000006 R_X86_64_GLOB_DAT 0000000000246100 dd_purezero_gmp + 0 And this in the .dynsym section: 109: 0000000000246100 0 OBJECT GLOBAL DEFAULT 23 dd_purezero 634: 0000000000246100 32 OBJECT GLOBAL DEFAULT 23 dd_purezero_gmp So dd_purezero is not, in fact, an undefined symbol. It is an alias to dd_purezero_gmp, which is defined and has the proper relocation type. So it looks like -Wl,-z,now is doing something to defeat the alias mechanism. Is that right? If so, do I have any other option besides disabling hardening for gfan? Is there some way to get aliases to play well with the hardening flags? Thanks, -- Jerry James http://www.jamezone.org/ -- devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/devel Fedora Code of Conduct: http://fedoraproject.org/code-of-conduct
