1 files changed, 15 insertions, 19 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index d4aac24cc469..94ed6e20bb53 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -122,9 +122,9 @@ static void __exit_signal(struct task_struct *tsk)
                  * We won't ever get here for the group leader, since it
                  * will have been the last reference on the signal_struct.
                  */
-                sig->utime = cputime_add(sig->utime, tsk->utime);
-                sig->stime = cputime_add(sig->stime, tsk->stime);
-                sig->gtime = cputime_add(sig->gtime, tsk->gtime);
+                sig->utime += tsk->utime;
+                sig->stime += tsk->stime;
+                sig->gtime += tsk->gtime;
                 sig->min_flt += tsk->min_flt;
                 sig->maj_flt += tsk->maj_flt;
                 sig->nvcsw += tsk->nvcsw;
@@ -680,8 +680,6 @@ static void exit_mm(struct task_struct * tsk)
         tsk->mm = NULL;
         up_read(&mm->mmap_sem);
         enter_lazy_tlb(mm, current);
-        /* We don't want this task to be frozen prematurely */
-        clear_freeze_flag(tsk);
         task_unlock(tsk);
         mm_update_next_owner(mm);
         mmput(mm);
@@ -1043,6 +1041,7 @@ NORET_TYPE void do_exit(long code)
         exit_rcu();
         /* causes final put_task_struct in finish_task_switch(). */
         tsk->state = TASK_DEAD;
+        tsk->flags |= PF_NOFREEZE;      /* tell freezer to ignore us */
         schedule();
         BUG();
         /* Avoid "noreturn function does return".  */
@@ -1258,19 +1257,9 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
                 spin_lock_irq(&p->real_parent->sighand->siglock);
                 psig = p->real_parent->signal;
                 sig = p->signal;
-                psig->cutime =
-                        cputime_add(psig->cutime,
-                        cputime_add(tgutime,
-                                    sig->cutime));
-                psig->cstime =
-                        cputime_add(psig->cstime,
-                        cputime_add(tgstime,
-                                    sig->cstime));
-                psig->cgtime =
-                        cputime_add(psig->cgtime,
-                        cputime_add(p->gtime,
-                        cputime_add(sig->gtime,
-                                    sig->cgtime)));
+                psig->cutime += tgutime + sig->cutime;
+                psig->cstime += tgstime + sig->cstime;
+                psig->cgtime += p->gtime + sig->gtime + sig->cgtime;
                 psig->cmin_flt +=
                         p->min_flt + sig->min_flt + sig->cmin_flt;
                 psig->cmaj_flt +=
@@ -1543,8 +1532,15 @@ static int wait_consider_task(struct wait_opts *wo, int ptrace,
         }
 
         /* dead body doesn't have much to contribute */
-        if (p->exit_state == EXIT_DEAD)
+        if (unlikely(p->exit_state == EXIT_DEAD)) {
+                /*
+                 * But do not ignore this task until the tracer does
+                 * wait_task_zombie()->do_notify_parent().
+                 */
+                if (likely(!ptrace) && unlikely(ptrace_reparented(p)))
+                        wo->notask_error = 0;
                 return 0;
+        }
 
         /* slay zombie? */
         if (p->exit_state == EXIT_ZOMBIE) {