Updated patch for Bug 13217 - thread apply all detach throws a SEGFAULT

[ali_anwar <ali_anwar at codesourcery dot com>]

Fixed a formating issue...

Attached patch is for Bug 13217 - "thread apply all detach throws a 
SEGFAULT".

Issue:
Segmentation fault was coming from invalid access to tp->* i.e "tp->ptid".

Fix:
Check if the thread is valid before we apply a command
Check for the thread count after executing a command on every thread

Testing:
* Tested on powerpc-linux as well as i686-pc-linux
* Also checked with valgrind

Test case:
Added a test case to test "thread apply all detach" command

Regards,
-Ali


Index: ChangeLog
===================================================================
RCS file: /cvs/src/src/ChangeLog,v
retrieving revision 1.1036
diff -u -r1.1036 ChangeLog
--- ChangeLog	21 Sep 2012 15:16:59 -0000	1.1036
+++ ChangeLog	26 Sep 2012 09:51:12 -0000
@@ -1,3 +1,9 @@
+2012-09-21  Ali Anwar  <ali_anwar@codesourcery.com>
+
+	PR threads/13217
+	* thread.c (thread_valid): New function.
+	(thread_apply_all_command): Check for valid thread and thread count.
+
 2012-09-21  Steve Ellcey  <sellcey@mips.com>
 
 	* configure.ac: Add mips*-mti-elf* target.
Index: gdb/thread.c
===================================================================
RCS file: /cvs/src/src/gdb/thread.c,v
retrieving revision 1.149
diff -u -r1.149 thread.c
--- gdb/thread.c	27 Jul 2012 00:52:36 -0000	1.149
+++ gdb/thread.c	26 Sep 2012 09:51:13 -0000
@@ -57,6 +57,7 @@
 struct thread_info *thread_list = NULL;
 static int highest_thread_num;
 
+static int thread_valid (struct thread_info *);
 static void thread_command (char *tidstr, int from_tty);
 static void thread_apply_all_command (char *, int);
 static int thread_alive (struct thread_info *);
@@ -73,6 +74,17 @@
   return tp;
 }
 
+/* Return true if TP is valid thread. */
+static int
+thread_valid (struct thread_info *tp)
+{
+  struct thread_info  *utp;
+  for (utp = thread_list; utp; utp = utp->next)
+     if (tp == utp)
+       return 1;
+  return 0;
+}
+
 void
 delete_step_resume_breakpoint (struct thread_info *tp)
 {
@@ -1193,7 +1205,7 @@
      execute_command.  */
   saved_cmd = xstrdup (cmd);
   make_cleanup (xfree, saved_cmd);
-  for (tp = thread_list; tp; tp = tp->next)
+  for (tp = thread_list; thread_valid(tp); tp = tp->next)
     if (thread_alive (tp))
       {
 	switch_to_thread (tp->ptid);
@@ -1203,6 +1215,8 @@
 	execute_command (cmd, from_tty);
 	strcpy (cmd, saved_cmd);	/* Restore exact command used
 					   previously.  */
+	if (thread_count() == 0)
+	  break;
       }
 
   do_cleanups (old_chain);
Index: gdb/testsuite/gdb.threads/threadapply.exp
===================================================================
RCS file: /cvs/src/src/gdb/testsuite/gdb.threads/threadapply.exp,v
retrieving revision 1.15
diff -u -r1.15 threadapply.exp
--- gdb/testsuite/gdb.threads/threadapply.exp	26 Jun 2012 19:23:20 -0000	1.15
+++ gdb/testsuite/gdb.threads/threadapply.exp	26 Sep 2012 09:51:14 -0000
@@ -63,3 +63,4 @@
 gdb_test "up" ".*in main.*" "go up in the stack frame" 
 gdb_test "thread apply all print 1"  "Thread ..*\\\$\[0-9]+ = 1.*Thread ..*\\\$\[0-9]+ = 1.*Thread ..*\\\$\[0-9]+ = 1.*Thread ..*\\\$\[0-9]+ = 1.*Thread ..*\\\$\[0-9]+ = 1.*Thread ..*\\\$\[0-9]+ = 1" "run a simple print command on all threads"
 gdb_test "down" "#0.*thread_function.*" "go down and check selected frame"
+gdb_test "thread apply all detach" "Detaching from.*" "detach all threads"