From: Stefan Liebler <stli@linux.vnet.ibm.com>
Date: Fri, 2 Dec 2016 08:09:55 +0000 (+0100)
Subject: Fix new testcase elf/tst-latepthread on s390x.
X-Git-Tag: glibc-2.25~240
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f91d3fd64d9b98054f5663a8fb533d15ca9f5943;p=thirdparty%2Fglibc.git

Fix new testcase elf/tst-latepthread on s390x.

The first dlopen ("tst-latepthreadmod.so", RTLD_LOCAL | RTLD_LAZY) call
in elf/tst-latepthread.c fails on s390x with "error: dlopen failed:
.../build-s390x/elf/tst-latepthreadmod.so:
undefined symbol: this_function_is_not_defined".

In elf/tst-latepthreadmod.c, this_function_is_not_defined is a sibling
call which leads to a R_390_GLOB_DAT relocation in .rela.dyn instead of
a R_390_JMP_SLOT in .rela.plt.

As RTLD_LAZY skips the JMP_SLOT relocations, but not GLOB_DAT ones,
the dlopen call fails. If elf/tst-latepthreadmod.c is build with
-fno-optimize-sibling-calls, a JMP_SLOT relocation is generated for
this_function_is_not_defined and the test passes.

ChangeLog:

	* elf/Makefile (CFLAGS-tst-latepthreadmod.c):
	Add -fno-optimize-sibling-calls.
---

diff --git a/ChangeLog b/ChangeLog
index 62e49bb03aa..f42d0c574d8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2016-12-02  Stefan Liebler  <stli@linux.vnet.ibm.com>
+
+	* elf/Makefile (CFLAGS-tst-latepthreadmod.c):
+	Add -fno-optimize-sibling-calls.
+
 2016-12-02  Joseph Myers  <joseph@codesourcery.com>
 
 	* math/bits/mathcalls.h [__GLIBC_USE (IEC_60559_BFP_EXT)] (llogb):
diff --git a/elf/Makefile b/elf/Makefile
index 33b003b170e..18b3e2a95d8 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -1271,6 +1271,9 @@ LDFLAGS-tst-audit12mod2.so = -Wl,--version-script=tst-audit12mod2.map
 # Force lazy binding for the same reason.
 LDFLAGS-tst-latepthreadmod.so = \
   -Wl,-z,lazy -Wl,--unresolved-symbols=ignore-all
+# Do not optimize sibling calls as the test relies on a JMP_SLOT relocation for
+# function this_function_is_not_defined.
+CFLAGS-tst-latepthreadmod.c = -fno-optimize-sibling-calls
 $(objpfx)tst-latepthreadmod.so: $(shared-thread-library)
 $(objpfx)tst-latepthread: $(libdl)
 $(objpfx)tst-latepthread.out: $(objpfx)tst-latepthreadmod.so