ptrace: kill real_parent_is_ptracer() in in favor of ptrace_reparented()

Kill real_parent_is_ptracer() and update the callers to use
ptrace_reparented(), after the previous patch they do the same.

Remove the unnecessary ->ptrace != 0 check in get_signal_to_deliver(),
if ptrace_reparented() == T then the task must be ptraced.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>

1 files changed, 4 insertions, 16 deletions

diff --git a/kernel/signal.c b/kernel/signal.c
index 4c4ad34caf77..0a1bf2c8bdcd 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1760,15 +1760,6 @@ static int sigkill_pending(struct task_struct *tsk)
 }
 
 /*
- * Test whether the target task of the usual cldstop notification - the
- * real_parent of @child - is in the same group as the ptracer.
- */
-static bool real_parent_is_ptracer(struct task_struct *child)
-{
-        return same_thread_group(child->parent, child->real_parent);
-}
-
-/*
  * This must be called with current->sighand->siglock held.
  *
  * This should be the path for all ptrace stops.
@@ -1848,7 +1839,7 @@ static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
                  * separately unless they're gonna be duplicates.
                  */
                 do_notify_parent_cldstop(current, true, why);
-                if (gstop_done && !real_parent_is_ptracer(current))
+                if (gstop_done && ptrace_reparented(current))
                         do_notify_parent_cldstop(current, false, why);
 
                 /*
@@ -2154,7 +2145,6 @@ relock:
          * the CLD_ si_code into SIGNAL_CLD_MASK bits.
          */
         if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
-                struct task_struct *leader;
                 int why;
 
                 if (signal->flags & SIGNAL_CLD_CONTINUED)
@@ -2175,13 +2165,11 @@ relock:
                  * a duplicate.
                  */
                 read_lock(&tasklist_lock);
-
                 do_notify_parent_cldstop(current, false, why);
 
-                leader = current->group_leader;
-                if (leader->ptrace && !real_parent_is_ptracer(leader))
-                        do_notify_parent_cldstop(leader, true, why);
-
+                if (ptrace_reparented(current->group_leader))
+                        do_notify_parent_cldstop(current->group_leader,
+                                                true, why);
                 read_unlock(&tasklist_lock);
 
                 goto relock;