Concrete Example Of DSO Linking Change in ld
I checked out a 'devel' version of Systemtap from :
:pserver:anonymous@cvs.fedproject.org:/cvs/pkgs
and ran 'make srpm' to produce a source rpm in order to do a mock build. I ran this build with the new binutils rpm (http://roland.fedorapeople.org/ld-test/) so that it would have the version of ld with the proposed changes. After running the build the following error appeared in the log file :
RPM build errors: /usr/bin/ld.bfd: stap.13165.test: undefined reference to symbol 'pthread_cancel@@GLIBC_2.0' /usr/bin/ld.bfd: note: 'pthread_cancel@@GLIBC_2.0' is defined in DSO /lib/libpthread.so.0 so try adding it to the linker command line /lib/libpthread.so.0: could not read symbols: Invalid operation *** /usr/bin/ld: ld behavior mismatch! *** *** /usr/bin/ld.bfd succeeeded *** *** /usr/bin/ld.bfd --no-add-needed exits 1 *** *** arguments: --eh-frame-hdr --build-id -m elf_i386 --hash-style=gnu -dynamic-linker /lib/ld-linux.so.2 -pie -o stap /usr/lib/gcc/i686-redhat-linux/4.4.2/../../../Scrt1.o /usr/lib/gcc/i686- redhat-linux/4.4.2/../../../crti.o /usr/lib/gcc/i686-redhat-linux/4.4.2/crtbeginS.o -L/usr/lib/gcc/i686-redhat-linux/4.4.2 -L/usr/lib/gcc/i686-redhat-linux/4.4.2 -L/usr/lib/gcc/i686-redhat- linux/4.4.2/../../.. -z relro -z now stap-main.o stap-parse.o stap-staptree.o stap-elaborate.o stap-translate.o stap-tapsets.o stap-buildrun.o stap-loc2c.o stap-hash.o stap-mdfour.o stap-cache.o stap-util.o stap-coveragedb.o stap-dwarf_wrappers.o stap-tapset-been.o stap-tapset-procfs.o stap-tapset-timers.o stap-tapset-perfmon.o stap-tapset-mark.o stap-tapset-itrace.o stap-tapset-utrace.o stap-task_finder.o stap-dwflpp.o stap-rpm_finder.o --start-group -ldw -lebl --end-group -lelf -lsqlite3 -lrpm -ldl -lstdc++ -lm -lgcc_s -lgcc -lc -lgcc_s -lgcc /usr/lib /gcc/i686-redhat-linux/4.4.2/crtendS.o /usr/lib/gcc/i686-redhat-linux/4.4.2/../../../crtn.o collect2: ld returned 1 exit status make[2]: *** [stap] Error 1 make[1]: *** [all-recursive] Error 1 make: *** [all] Error 2
So this would seem to indicate that the version of Systemtap used was using /lib/libpthread.so.0 without explicitly linking to it. The solution would be to simply ensure that any binaries that use lpthread.so, has a -lpthread added when linking is happening.
Simpler Concrete Example Of DSO Linking Change in ld
I checked out a 'devel' version of deltarpm from :
:pserver:anonymous@cvs.fedproject.org:/cvs/pkgs
and ran 'make srpm' to produce a source rpm in order to do a mock build. I ran this build with the new binutils rpm (http://roland.fedorapeople.org/ld-test/) so that it would have the version of ld with the proposed changes. After running the build the following error appeared in the log file :
RPM build errors: /usr/bin/ld.bfd: rpmdumpheader.o: undefined reference to symbol 'Fopen' /usr/bin/ld.bfd: note: 'Fopen' is defined in DSO /usr/lib/librpmio.so.0 so try adding it to the linker command line /usr/lib/librpmio.so.0: could not read symbols: Invalid operation *** /usr/bin/ld: ld behavior mismatch! *** *** /usr/bin/ld.bfd succeeeded *** *** /usr/bin/ld.bfd --no-add-needed exits 1 *** *** arguments: --eh-frame-hdr --build-id -m elf_i386 --hash-style=gnu -dynamic-linker /lib/ld-linux.so.2 -o rpmdumpheader /usr/lib/gcc/i686-redhat-linux/4.4.2/../../../crt1.o /usr/lib/gcc/i686-redhat-linux/4.4.2/../../../crti.o /usr/lib/gcc/i686-redhat-linux/4.4.2/crtbegin.o -L/usr/lib/gcc/i686-redhat-linux/4.4.2 -L/usr/lib/gcc/i686-redhat-linux/4.4.2 -L/usr/lib/gcc/i686-redhat-linux/4.4.2/../../.. rpmdumpheader.o -lrpm -lgcc --as-needed -lgcc_s --no-as-needed -lc -lgcc --as-needed -lgcc_s --no-as-needed /usr/lib/gcc/i686-redhat-linux/4.4.2/crtend.o /usr/lib/gcc/i686-redhat-linux/4.4.2/../../../crtn.o collect2: ld returned 1 exit status make: *** [rpmdumpheader] Error 1
So this would seem to indicate that the version of deltarpm used was using /usr/lib/librpmio.so.0 without explicitly linking to it. The solution would be to simply ensure that any binaries that use librpmio.so, have a -lrpmio added when linking is happening.
Making the following change to the Makefile fixes this problem :
rpmdumpheader: rpmdumpheader.o - $(CC) $(LDFLAGS) $^ -lrpm -o $@ + $(CC) $(LDFLAGS) $^ -lrpm -lrpmio -o $@