[PATCH] cpuset fork locking fix

Move the cpuset_fork() call below the write_unlock_irq call in
kernel/fork.c copy_process().

Since the cpuset-dual-semaphore-locking-overhaul.patch, the cpuset_fork()
routine acquires task_lock(), so cannot be called while holding the
tasklist_lock for write.
Signed-off-by: NPaul Jackson <pj@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

kernel/fork.c

@@ -1124,8 +1124,6 @@ static task_t *copy_process(unsigned long clone_flags,
 	if (unlikely(p->ptrace & PT_PTRACED))
 		__ptrace_link(p, current->parent);
 
-	cpuset_fork(p);
-
 	attach_pid(p, PIDTYPE_PID, p->pid);
 	attach_pid(p, PIDTYPE_TGID, p->tgid);
 	if (thread_group_leader(p)) {
@@ -1142,6 +1140,7 @@ static task_t *copy_process(unsigned long clone_flags,
 	total_forks++;
 	write_unlock_irq(&tasklist_lock);
 	proc_fork_connector(p);
+	cpuset_fork(p);
 	retval = 0;
 
 fork_out: