uprobes: Change the callsite of uprobe_copy_process()

Preparation for the next patches.

Move the callsite of uprobe_copy_process() in copy_process() down
to the succesfull return. We do not care if copy_process() fails,
uprobe_free_utask() won't be called in this case so the wrong
->utask != NULL doesn't matter.

OTOH, with this change we know that copy_process() can't fail when
uprobe_copy_process() is called, the new task should either return
to user-mode or call do_exit(). This way uprobe_copy_process() can:

	1. setup p->utask != NULL if necessary

	2. setup uprobes_state.xol_area

	3. use task_work_add(p)

Also, move the definition of uprobe_copy_process() down so that it
can see get_utask().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index 086fe73ad6b..d3603b81246 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1373,7 +1373,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 	INIT_LIST_HEAD(&p->pi_state_list);
 	p->pi_state_cache = NULL;
 #endif
-	uprobe_copy_process(p);
 	/*
 	 * sigaltstack should be cleared when sharing the same VM
 	 */
@@ -1490,6 +1489,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 	perf_event_fork(p);
 
 	trace_task_newtask(p, clone_flags);
+	uprobe_copy_process(p);
 
 	return p;