http://sourceware.org/ml/gdb-patches/2009-10/msg00142.html

Subject: [patch] Fix GNU/Linux core open: Can't read pathname for load map:  Input/output error.

[ New patch variant.  ]

Index: gdb-7.5.50.20130118/gdb/solib-svr4.c

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

--- gdb-7.5.50.20130118.orig/gdb/solib-svr4.c	2013-01-18 23:05:19.414210015 +0100

+++ gdb-7.5.50.20130118/gdb/solib-svr4.c	2013-01-18 23:05:34.813231664 +0100

@@ -1221,8 +1221,17 @@ svr4_read_so_list (CORE_ADDR lm, struct

 			  SO_NAME_MAX_PATH_SIZE - 1, &errcode);

       if (errcode != 0)

 	{

-	  warning (_("Can't read pathname for load map: %s."),

-		   safe_strerror (errcode));

+	  /* During the first ever DSO list reading some strings may be

+	     unreadable as residing in the ld.so readonly memory not being

+	     present in a dumped core file.  Delay the error check after

+	     the first pass of DSO list scanning when ld.so should be

+	     already mapped in and all the DSO list l_name memory gets

+	     readable.  */

+

+	  if (master_so_list () != NULL)

+	    warning (_("Can't read pathname for load map: %s."),

+		     safe_strerror (errcode));

+

 	  do_cleanups (old_chain);

 	  continue;

 	}

Index: gdb-7.5.50.20130118/gdb/solib.c

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

--- gdb-7.5.50.20130118.orig/gdb/solib.c	2013-01-18 23:05:19.415210017 +0100

+++ gdb-7.5.50.20130118/gdb/solib.c	2013-01-18 23:05:57.421263173 +0100

@@ -666,7 +666,7 @@ solib_used (const struct so_list *const

    processes we've just attached to, so that's okay.  */

 static void

-update_solib_list (int from_tty, struct target_ops *target)

+update_solib_list_1 (int from_tty, struct target_ops *target)

 {

   struct target_so_ops *ops = solib_ops (target_gdbarch ());

   struct so_list *inferior = ops->current_sos();

@@ -837,6 +837,21 @@ Do you need \"set solib-search-path\" or

     }

 }

+/* Wrapper for Fedora: gdb-core-open-vdso-warning.patch  */

+

+static void

+update_solib_list (int from_tty, struct target_ops *target)

+{

+  struct so_list *saved_so_list_head = so_list_head;

+

+  update_solib_list_1 (from_tty, target);

+

+  /* If this was the very first DSO list scan and we possibly read in ld.so

+     recheck all the formerly unreadable DSO names strings.  */

+

+  if (saved_so_list_head == NULL && so_list_head != NULL)

+    update_solib_list_1 (from_tty, target);

+}

 /* Return non-zero if NAME is the libpthread shared library.

Index: gdb-7.5.50.20130118/gdb/testsuite/gdb.base/corefile.exp

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

--- gdb-7.5.50.20130118.orig/gdb/testsuite/gdb.base/corefile.exp	2013-01-18 23:05:19.416210020 +0100

+++ gdb-7.5.50.20130118/gdb/testsuite/gdb.base/corefile.exp	2013-01-18 23:05:34.814231667 +0100

@@ -286,3 +286,19 @@ if {$buildid == ""} {

     gdb_test "info files" "Local exec file:\r\n\[ \t\]*`[string_to_regexp $debugdir/$buildid]', file type .*"

     pass $wholetest

 }

+

+

+# Test Linux specific vDSO warning:

+# warning: Can't read pathname for load map: Input/output error.

+

+clean_restart ${testfile}

+

+set test "core-file vdso warning"

+gdb_test_multiple "core-file $corefile" $test {

+    -re "warning: Can't read pathname for load map: Input/output error\\.\r\n.*\r\n$gdb_prompt $" {

+	fail $test

+    }

+    -re "\r\n$gdb_prompt $" {

+	pass $test

+    }

+}

Index: gdb-7.5.50.20130118/gdb/testsuite/gdb.base/solib-symbol.exp

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

--- gdb-7.5.50.20130118.orig/gdb/testsuite/gdb.base/solib-symbol.exp	2013-01-18 23:05:19.416210020 +0100

+++ gdb-7.5.50.20130118/gdb/testsuite/gdb.base/solib-symbol.exp	2013-01-18 23:05:34.814231667 +0100

@@ -27,7 +27,8 @@ set lib_flags [list debug ldflags=-Wl,-B

 # Binary file.

 set testfile "solib-symbol-main"

 set srcfile ${srcdir}/${subdir}/${testfile}.c

-set binfile ${objdir}/${subdir}/${testfile}

+set executable ${testfile}

+set binfile ${objdir}/${subdir}/${executable}

 set bin_flags [list debug shlib=${binfile_lib}]

 if [get_compiler_info] {

@@ -72,8 +73,26 @@ gdb_test "br foo2" \

 	 "Breakpoint.*: foo2. .2 locations..*" \

 	 "foo2 in mdlib"

-gdb_exit

+# Test GDB warns for shared libraris which have not been found.

-return 0

+gdb_test "info sharedlibrary" "/${libname}.*"

+clean_restart ${executable}

+gdb_breakpoint "main"

+gdb_run_cmd

+set test "no warning for missing libraries"

+gdb_test_multiple "" $test {

+    -re "warning: Could not load shared library symbols for \[0-9\]+ libraries,.*\r\n$gdb_prompt $" {

+	fail $test

+    }

+    -re "Breakpoint \[0-9\]+, main .*\r\n$gdb_prompt $" {

+	pass $test

+    }

+}

+clean_restart ${executable}

+gdb_test_no_output "set solib-absolute-prefix /doESnotEXIST"

+gdb_breakpoint "main"

+gdb_run_cmd

+gdb_test "" "warning: Could not load shared library symbols for \[0-9\]+ libraries,.*\r\nBreakpoint \[0-9\]+, main .*" \

+	 "warning for missing libraries"