This bug is already fixed in the RHEL-7.1 GDB version.  However, it is

also important to add a testcase, so the following is a patch to add

this test.

This is the original message submitted to gdb-patches:

    From: Sergio Durigan Junior <sergiodj at redhat dot com>

    To: GDB Patches <gdb-patches at sourceware dot org>

    Subject: [PATCH] Add test for global variable that is nested by another DSO

    Date: Thu,  4 Sep 2014 17:32:53 -0400

    Message-Id: <1409866373-16413-1-git-send-email-sergiodj@redhat.com>

    This is just a testcase addition that I am proposing for upstream GDB.

    We have this in our internal tree, and the related RH bug is:

      <https://bugzilla.redhat.com/show_bug.cgi?id=809179>

    (You might not be able to see all the comments without privileges.)

    This bug is about a global variable that got incorrectly displayed by

    GDB.  This bug has already been fixed a long time ago by Joel's

    commit:

      commit 19630284f570790ebf6d50bfb43caa1f125ee88a

      Author: Joel Brobecker <brobecker@gnat.com>

      Date:   Tue Jun 5 13:50:50 2012 +0000

    But I think a testcase for it wouldn't hurt.

    So, consider the following scenario:

      $ cat solib1.c

      int test;

      void c_main (void)

      {

        test = 42;

      }

      $ cat solib2.c

      int test;

      void b_main (void)

      {

        test = 42;

      }

      $ cat main.c

      int main (int argc, char *argv[])

      {

        c_main ();

        b_main ();

        return 0;

      }

      $ gcc -g -fPIC -shared -o libSO1.so -c solib1.c

      $ gcc -g -fPIC -shared -o libSO2.so -c solib2.c

      $ gcc -g -o main -L$PWD -lSO1 -lSO2 main.c

      $ LD_LIBRARY_PATH=. gdb -q -batch -ex 'b c_main' -ex r -ex n -ex 'p test' ./main

      ...

      $1 = 0

    This happened with GDB before Joel's commit above.  Now, things work

    and GDB is able to correctly display the nested global variable:

      $ LD_LIBRARY_PATH=. gdb -q -batch -ex 'b c_main' -ex r -ex n -ex 'p test' ./main

      ...

      $1 = 42

    The testcase attached tests this behavior.

    gdb/testsuite/ChangeLog:

    2014-09-04  Sergio Durigan Junior  <sergiodj@redhat.com>

    	* gdb.base/global-var-nested-by-dso-solib1.c: New file.

    	* gdb.base/global-var-nested-by-dso-solib2.c: Likewise.

    	* gdb.base/global-var-nested-by-dso.c: Likewise.

    	* gdb.base/global-var-nested-by-dso.exp: Likewise.

Index: gdb-7.6.1/gdb/testsuite/gdb.base/global-var-nested-by-dso-solib1.c

===================================================================

--- /dev/null

+++ gdb-7.6.1/gdb/testsuite/gdb.base/global-var-nested-by-dso-solib1.c

@@ -0,0 +1,24 @@

+/* Copyright 2014 Free Software Foundation, Inc.

+

+   This file is part of GDB.

+

+   This program is free software; you can redistribute it and/or modify

+   it under the terms of the GNU General Public License as published by

+   the Free Software Foundation; either version 3 of the License, or

+   (at your option) any later version.

+

+   This program is distributed in the hope that it will be useful,

+   but WITHOUT ANY WARRANTY; without even the implied warranty of

+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

+   GNU General Public License for more details.

+

+   You should have received a copy of the GNU General Public License

+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

+

+int test;

+

+void

+c_main (void)

+{

+  test = 42;

+}

Index: gdb-7.6.1/gdb/testsuite/gdb.base/global-var-nested-by-dso-solib2.c

===================================================================

--- /dev/null

+++ gdb-7.6.1/gdb/testsuite/gdb.base/global-var-nested-by-dso-solib2.c

@@ -0,0 +1,24 @@

+/* Copyright 2014 Free Software Foundation, Inc.

+

+   This file is part of GDB.

+

+   This program is free software; you can redistribute it and/or modify

+   it under the terms of the GNU General Public License as published by

+   the Free Software Foundation; either version 3 of the License, or

+   (at your option) any later version.

+

+   This program is distributed in the hope that it will be useful,

+   but WITHOUT ANY WARRANTY; without even the implied warranty of

+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

+   GNU General Public License for more details.

+

+   You should have received a copy of the GNU General Public License

+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

+

+int test;

+

+void

+b_main (void)

+{

+  test = 42;

+}

Index: gdb-7.6.1/gdb/testsuite/gdb.base/global-var-nested-by-dso.c

===================================================================

--- /dev/null

+++ gdb-7.6.1/gdb/testsuite/gdb.base/global-var-nested-by-dso.c

@@ -0,0 +1,24 @@

+/* Copyright 2014 Free Software Foundation, Inc.

+

+   This file is part of GDB.

+

+   This program is free software; you can redistribute it and/or modify

+   it under the terms of the GNU General Public License as published by

+   the Free Software Foundation; either version 3 of the License, or

+   (at your option) any later version.

+

+   This program is distributed in the hope that it will be useful,

+   but WITHOUT ANY WARRANTY; without even the implied warranty of

+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

+   GNU General Public License for more details.

+

+   You should have received a copy of the GNU General Public License

+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

+

+int

+main (int argc, char *argv[])

+{

+  c_main ();

+  b_main ();

+  return 0;

+}

Index: gdb-7.6.1/gdb/testsuite/gdb.base/global-var-nested-by-dso.exp

===================================================================

--- /dev/null

+++ gdb-7.6.1/gdb/testsuite/gdb.base/global-var-nested-by-dso.exp

@@ -0,0 +1,55 @@

+# Copyright 2014 Free Software Foundation, Inc.

+

+# This program is free software; you can redistribute it and/or modify

+# it under the terms of the GNU General Public License as published by

+# the Free Software Foundation; either version 3 of the License, or

+# (at your option) any later version.

+#

+# This program is distributed in the hope that it will be useful,

+# but WITHOUT ANY WARRANTY; without even the implied warranty of

+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

+# GNU General Public License for more details.

+#

+# You should have received a copy of the GNU General Public License

+# along with this program.  If not, see <http://www.gnu.org/licenses/>.

+

+if { [skip_shlib_tests] } {

+    return 0

+}

+

+standard_testfile

+

+set lib1name $testfile-solib1

+set srcfile_lib1 $srcdir/$subdir/$lib1name.c

+set binfile_lib1 [standard_output_file $lib1name.so]

+

+set lib2name $testfile-solib2

+set srcfile_lib2 $srcdir/$subdir/$lib2name.c

+set binfile_lib2 [standard_output_file $lib2name.so]

+

+if { [gdb_compile_shlib $srcfile_lib1 $binfile_lib1 \

+	[list debug additional_flags=-fPIC]] != "" } {

+  untested "Could not compile $binfile_lib1."

+  return -1

+}

+

+if { [gdb_compile_shlib $srcfile_lib2 $binfile_lib2 \

+	[list debug additional_flags=-fPIC]] != "" } {

+  untested "Could not compile $binfile_lib2."

+  return -1

+}

+

+if { [gdb_compile $srcdir/$subdir/$srcfile $binfile executable \

+	[list debug shlib=$binfile_lib1 shlib=$binfile_lib2]] != "" } {

+  return -1

+}

+

+clean_restart $binfile

+

+if { ![runto_main] } {

+  return -1

+}

+

+gdb_test "next" "$decimal.*b_main \\(\\);"

+gdb_test "next" "$decimal.*return 0;"

+gdb_test "print test" " = 42"