Hi,
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?
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
