gdb/gdb-6.6-buildid-locate-solib-missing-ids.patch

From FEDORA_PATCHES Mon Sep 17 00:00:00 2001
From: Fedora GDB patches <invalid@email.com>
Date: Fri, 27 Oct 2017 21:07:50 +0200
Subject: gdb-6.6-buildid-locate-solib-missing-ids.patch

;; Fix loading of core files without build-ids but with build-ids in executables.
;; Load strictly build-id-checked core files only if no executable is specified
;; (Jan Kratochvil, RH BZ 1339862).
;;=push+jan

gdb returns an incorrect back trace when applying a debuginfo
https://bugzilla.redhat.com/show_bug.cgi?id=1339862

diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c
--- a/gdb/solib-svr4.c
+++ b/gdb/solib-svr4.c
@@ -1350,14 +1350,28 @@ svr4_read_so_list (svr4_info *info, CORE_ADDR lm, CORE_ADDR prev_lm,
 	}
 
       {
-	struct bfd_build_id *build_id;
+	struct bfd_build_id *build_id = NULL;
 
 	strncpy (newobj->so_original_name, buffer.get (), 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 (((lm_info_svr4 *) 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 (current_program_space->symfile_object_file != NULL
+	    && (current_program_space->symfile_object_file->flags
+	         & OBJF_BUILD_ID_CORE_LOADED) != 0)
+	  build_id = build_id_addr_get (li->l_ld);
 	if (build_id != NULL)
 	  {
 	    char *name, *build_id_filename;
@@ -1372,23 +1386,7 @@ svr4_read_so_list (svr4_info *info, CORE_ADDR lm, CORE_ADDR prev_lm,
 		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 (current_program_space->symfile_object_file != NULL
-		    && (current_program_space->symfile_object_file->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);
diff --git a/gdb/testsuite/gdb.base/gcore-buildid-exec-but-not-solib-lib.c b/gdb/testsuite/gdb.base/gcore-buildid-exec-but-not-solib-lib.c
new file mode 100644
--- /dev/null
+++ b/gdb/testsuite/gdb.base/gcore-buildid-exec-but-not-solib-lib.c
@@ -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)
+{
+}
diff --git a/gdb/testsuite/gdb.base/gcore-buildid-exec-but-not-solib-main.c b/gdb/testsuite/gdb.base/gcore-buildid-exec-but-not-solib-main.c
new file mode 100644
--- /dev/null
+++ b/gdb/testsuite/gdb.base/gcore-buildid-exec-but-not-solib-main.c
@@ -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;
+}
diff --git a/gdb/testsuite/gdb.base/gcore-buildid-exec-but-not-solib.exp b/gdb/testsuite/gdb.base/gcore-buildid-exec-but-not-solib.exp
new file mode 100644
--- /dev/null
+++ b/gdb/testsuite/gdb.base/gcore-buildid-exec-but-not-solib.exp
@@ -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"