Hi, On Sat, 2021-11-20 at 15:18 +0100, Mark Wielaard wrote: > On Sat, Nov 20, 2021 at 01:12:17AM +0300, Dmitry V. Levin wrote: > > On Fri, Nov 19, 2021 at 05:58:19PM +0100, Florian Weimer wrote: > > > It may have to do with --as-needed that some builds use. If there are > > > no pending undefined references, some linkers drop earlier shared object > > > references with --as-needed (similar to what happens with static > > > archives). > > > > > > The GCC LTO plugin results in ld looking at more objects in greater > > > detail for some reason. Without LTO and --as-needed, you probably don't > > > get a dlopen export (if you do not link with -E) because indirect > > > dependencies are not consulted, breaking the valgrind workaround because > > > there is no interposition. > > > > Thanks. I suppose adding -rdynamic to dwfl_proc_attach_LDFLAGS should be > > a more correct fix. > > That works. But I don't really understand why. > Does the attached patch look OK to you?
I decided to simply disable LTO on Fedora 34, but still would like feedback on this patch. Thanks, Mark
>From 311b42279d42187540e776648fd19c1e897fbacd Mon Sep 17 00:00:00 2001 From: Mark Wielaard <m...@klomp.org> Date: Thu, 18 Nov 2021 21:34:57 +0100 Subject: [PATCH] tests: Add -rdynamic to dwfl_proc_attach_LDFLAGS dwfl-proc-attach uses (overrides) dlopen (so it does nothing). This seems to cause a versioned dlopen symbol to be pulled in when building with LTO. Resulting in a link failure (when dlopen isn't integrated into libc): /usr/bin/ld: dwfl-proc-attach.o (symbol from plugin): undefined reference to symbol 'dlopen@@GLIBC_2.2.5' /usr/bin/ld: /usr/lib64/libdl.so.2: error adding symbols: DSO missing from command line collect2: error: ld returned 1 exit status Add -rdynamic to the LDFLAGS to add all symbols to the dynamic symbol table for dwfl-proc-attach. Signed-off-by: Mark Wielaard <m...@klomp.org> --- tests/ChangeLog | 4 ++++ tests/Makefile.am | 2 +- 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/tests/ChangeLog b/tests/ChangeLog index a59cdd51..d0fc3fb0 100644 --- a/tests/ChangeLog +++ b/tests/ChangeLog @@ -1,3 +1,7 @@ +2021-11-18 Mark Wielaard <m...@klomp.org> + + * Makefile.am (dwfl_proc_attach_LDFLAGS): Add -rdynamic. + 2021-11-05 Frank Ch. Eigler <f...@redhat.com> PR28430 diff --git a/tests/Makefile.am b/tests/Makefile.am index bfb8b13a..2298a5ae 100644 --- a/tests/Makefile.am +++ b/tests/Makefile.am @@ -717,7 +717,7 @@ strptr_LDADD = $(libelf) newdata_LDADD = $(libelf) elfstrtab_LDADD = $(libelf) dwfl_proc_attach_LDADD = $(libdw) -dwfl_proc_attach_LDFLAGS = -pthread $(AM_LDFLAGS) +dwfl_proc_attach_LDFLAGS = -pthread -rdynamic $(AM_LDFLAGS) elfshphehdr_LDADD =$(libelf) elfstrmerge_LDADD = $(libdw) $(libelf) dwelfgnucompressed_LDADD = $(libelf) $(libdw) -- 2.30.2
