gdb returns an incorrect back trace when applying a debuginfo

https://bugzilla.redhat.com/show_bug.cgi?id=1339862

Index: gdb-7.9.90.20150709/gdb/solib-svr4.c

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

--- gdb-7.9.90.20150709.orig/gdb/solib-svr4.c	2015-07-09 18:18:54.526417766 +0200

+++ gdb-7.9.90.20150709/gdb/solib-svr4.c	2015-07-09 18:19:33.074746586 +0200

@@ -1381,14 +1381,27 @@ svr4_read_so_list (CORE_ADDR lm, CORE_AD

 	}

       {

-	struct bfd_build_id *build_id;

+	struct bfd_build_id *build_id = NULL;

 	strncpy (newobj->so_original_name, buffer, SO_NAME_MAX_PATH_SIZE - 1);

 	newobj->so_original_name[SO_NAME_MAX_PATH_SIZE - 1] = '\0';

 	/* May get overwritten below.  */

 	strcpy (newobj->so_name, newobj->so_original_name);

-	build_id = build_id_addr_get (newobj->lm_info->l_ld);

+	/* In the case the main executable was found according to its build-id

+	   (from a core file) prevent loading a different build of a library

+	   with accidentally the same SO_NAME.

+

+	   It suppresses bogus backtraces (and prints "??" there instead) if

+	   the on-disk files no longer match the running program version.

+

+	   If the main executable was not loaded according to its build-id do

+	   not do any build-id checking of the libraries.  There may be missing

+	   build-ids dumped in the core file and we would map all the libraries

+	   to the only existing file loaded that time - the executable.  */

+	if (symfile_objfile != NULL

+	    && (symfile_objfile->flags & OBJF_BUILD_ID_CORE_LOADED) != 0)

+	  build_id = build_id_addr_get (newobj->lm_info->l_ld);

 	if (build_id != NULL)

 	  {

 	    char *name, *build_id_filename;

@@ -1403,23 +1416,7 @@ svr4_read_so_list (CORE_ADDR lm, CORE_AD

 		xfree (name);

 	      }

 	    else

-	      {

-		debug_print_missing (newobj->so_name, build_id_filename);

-

-		/* In the case the main executable was found according to

-		   its build-id (from a core file) prevent loading

-		   a different build of a library with accidentally the

-		   same SO_NAME.

-

-		   It suppresses bogus backtraces (and prints "??" there

-		   instead) if the on-disk files no longer match the

-		   running program version.  */

-

-		if (symfile_objfile != NULL

-		    && (symfile_objfile->flags

-			& OBJF_BUILD_ID_CORE_LOADED) != 0)

-		  newobj->so_name[0] = 0;

-	      }

+	      debug_print_missing (newobj->so_name, build_id_filename);

 	    xfree (build_id_filename);

 	    xfree (build_id);

--- /dev/null	2016-07-02 20:29:01.679404943 +0200

+++ gdb-7.11.50.20160721/gdb/testsuite/gdb.base/gcore-buildid-exec-but-not-solib.exp	2016-07-31 23:04:49.062753722 +0200

@@ -0,0 +1,105 @@

+# Copyright 2016 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

+}

+

+set testfile "gcore-buildid-exec-but-not-solib"

+set srcmainfile ${testfile}-main.c

+set srclibfile ${testfile}-lib.c

+set libfile [standard_output_file ${testfile}-lib.so]

+set objfile [standard_output_file ${testfile}-main.o]

+set executable ${testfile}-main

+set binfile [standard_output_file ${executable}]

+set gcorefile [standard_output_file ${executable}.gcore]

+set outdir [file dirname $binfile]

+

+if { [gdb_compile_shlib ${srcdir}/${subdir}/${srclibfile} ${libfile} "debug additional_flags=-Wl,--build-id"] != ""

+     || [gdb_compile ${srcdir}/${subdir}/${srcmainfile} ${objfile} object {debug}] != "" } {

+     unsupported "-Wl,--build-id compilation failed"

+     return -1

+}

+set opts [list debug shlib=${libfile} "additional_flags=-Wl,--build-id"]

+if { [gdb_compile ${objfile} ${binfile} executable $opts] != "" } {

+     unsupported "-Wl,--build-id compilation failed"

+     return -1

+}

+

+clean_restart $executable

+gdb_load_shlib $libfile

+

+# Does this gdb support gcore?

+set test "help gcore"

+gdb_test_multiple $test $test {

+    -re "Undefined command: .gcore.*\r\n$gdb_prompt $" {

+	# gcore command not supported -- nothing to test here.

+	unsupported "gdb does not support gcore on this target"

+	return -1;

+    }

+    -re "Save a core file .*\r\n$gdb_prompt $" {

+	pass $test

+    }

+}

+

+if { ![runto lib] } then {

+    return -1

+}

+

+set escapedfilename [string_to_regexp ${gcorefile}]

+

+set test "save a corefile"

+gdb_test_multiple "gcore ${gcorefile}" $test {

+    -re "Saved corefile ${escapedfilename}\r\n$gdb_prompt $" {

+	pass $test

+    }

+    -re "Can't create a corefile\r\n$gdb_prompt $" {

+	unsupported $test

+	return -1

+    }

+}

+

+# Now restart gdb and load the corefile.

+

+clean_restart $executable

+gdb_load_shlib $libfile

+

+set buildid [build_id_debug_filename_get $libfile]

+

+regsub {\.debug$} $buildid {} buildid

+

+set debugdir [standard_output_file ${testfile}-debugdir]

+file delete -force -- $debugdir

+

+file mkdir $debugdir/[file dirname $libfile]

+file copy $libfile $debugdir/${libfile}

+

+file mkdir $debugdir/[file dirname $buildid]

+file copy $libfile $debugdir/${buildid}

+

+remote_exec build "ln -s /lib       ${debugdir}/"

+remote_exec build "ln -s /lib64     ${debugdir}/"

+# /usr is not needed, all the libs are in /lib64: libm.so.6 libc.so.6 ld-linux-x86-64.so.2

+

+gdb_test "set solib-absolute-prefix $debugdir"

+

+gdb_test_no_output "set debug-file-directory $debugdir" "set debug-file-directory"

+

+gdb_test "core ${gcorefile}" "Core was generated by .*" "re-load generated corefile"

+

+gdb_test "frame" "#0 \[^\r\n\]* lib .*" "library got loaded"

+

+gdb_test "bt"

+gdb_test "info shared"

--- /dev/null	2016-07-02 20:29:01.679404943 +0200

+++ gdb-7.11.50.20160721/gdb/testsuite/gdb.base/gcore-buildid-exec-but-not-solib-main.c	2016-07-28 21:06:40.977786922 +0200

@@ -0,0 +1,25 @@

+/* Copyright 2010 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/>.  */

+

+extern void lib (void);

+

+int

+main (void)

+{

+  lib ();

+  return 0;

+}

--- /dev/null	2016-07-02 20:29:01.679404943 +0200

+++ gdb-7.11.50.20160721/gdb/testsuite/gdb.base/gcore-buildid-exec-but-not-solib-lib.c	2016-07-28 21:06:40.977786922 +0200

@@ -0,0 +1,21 @@

+/* Copyright 2010 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/>.  */

+

+void

+lib (void)

+{

+}