2008-03-18  Pedro Alves  <pedro@codesourcery.com>

	gdb/
	* linux-nat.c (linux_child_follow_fork): Update inferior_ptid with
	the thread id.

	gdb/testsuite/
	gdb.threads/fork-child-threads.exp: Add "next" test.

---
 gdb/linux-nat.c                                  |    9 +++++++++
 gdb/testsuite/gdb.threads/fork-child-threads.exp |    1 +
 2 files changed, 10 insertions(+)

Index: src/gdb/testsuite/gdb.threads/fork-child-threads.exp
===================================================================
--- src.orig/gdb/testsuite/gdb.threads/fork-child-threads.exp	2008-03-18 18:31:12.000000000 +0000
+++ src/gdb/testsuite/gdb.threads/fork-child-threads.exp	2008-03-18 18:31:53.000000000 +0000
@@ -38,6 +38,7 @@ if ![runto_main] then {
 
 gdb_test "set follow-fork-mode child"
 gdb_breakpoint "start"
+gdb_test "next" ".*pthread_create \\(&thread, NULL, start, NULL\\);.*" "next over fork"
 gdb_test "continue" "Breakpoint 2, start.*" "get to the spawned thread"
 
 # Wrong:
Index: src/gdb/linux-nat.c
===================================================================
--- src.orig/gdb/linux-nat.c	2008-03-18 20:25:45.000000000 +0000
+++ src/gdb/linux-nat.c	2008-03-18 20:26:04.000000000 +0000
@@ -104,6 +104,8 @@ static LONGEST (*super_xfer_partial) (st
 				      const gdb_byte *,
 				      ULONGEST, LONGEST);
 
+static int find_thread_from_lwp (struct thread_info *thr, void *dummy);
+
 static int debug_linux_nat;
 static void
 show_debug_linux_nat (struct ui_file *file, int from_tty,
@@ -460,6 +462,7 @@ linux_child_follow_fork (struct target_o
   else
     {
       char child_pid_spelling[40];
+      struct thread_info *thr;
 
       /* Needed to keep the breakpoint lists in sync.  */
       if (! has_vforked)
@@ -519,6 +522,12 @@ linux_child_follow_fork (struct target_o
       linux_nat_switch_fork (inferior_ptid);
       check_for_thread_db ();
 
+      /* Update inferior_ptid to include the thread id, so updating
+	 step-resume breakpoints in the child works.  */
+      thr = iterate_over_threads (find_thread_from_lwp, &inferior_ptid);
+      if (thr)
+	inferior_ptid = thr->ptid;
+
       /* Reset breakpoints in the child as appropriate.  */
       follow_inferior_reset_breakpoints ();
     }