1 files changed, 22 insertions, 14 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index d8bd3b425fa7..2f59cc334516 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -72,6 +72,18 @@ static void __unhash_process(struct task_struct *p, bool group_dead)
                 list_del_rcu(&p->tasks);
                 list_del_init(&p->sibling);
                 __this_cpu_dec(process_counts);
+                /*
+                 * If we are the last child process in a pid namespace to be
+                 * reaped, notify the reaper sleeping zap_pid_ns_processes().
+                 */
+                if (IS_ENABLED(CONFIG_PID_NS)) {
+                        struct task_struct *parent = p->real_parent;
+
+                        if ((task_active_pid_ns(parent)->child_reaper == parent) &&
+                            list_empty(&parent->children) &&
+                            (parent->flags & PF_EXITING))
+                                wake_up_process(parent);
+                }
         }
         list_del_rcu(&p->thread_group);
 }
@@ -643,6 +655,7 @@ static void exit_mm(struct task_struct * tsk)
         mm_release(tsk, mm);
         if (!mm)
                 return;
+        sync_mm_rss(mm);
         /*
          * Serialize with any possible pending coredump.
          * We must hold mmap_sem around checking core_state
@@ -719,12 +732,6 @@ static struct task_struct *find_new_reaper(struct task_struct *father)
 
                 zap_pid_ns_processes(pid_ns);
                 write_lock_irq(&tasklist_lock);
-                /*
-                 * We can not clear ->child_reaper or leave it alone.
-                 * There may by stealth EXIT_DEAD tasks on ->children,
-                 * forget_original_parent() must move them somewhere.
-                 */
-                pid_ns->child_reaper = init_pid_ns.child_reaper;
         } else if (father->signal->has_child_subreaper) {
                 struct task_struct *reaper;
 
@@ -884,9 +891,9 @@ static void check_stack_usage(void)
 
         spin_lock(&low_water_lock);
         if (free < lowest_to_date) {
-                printk(KERN_WARNING "%s used greatest stack depth: %lu bytes "
-                                "left\n",
-                                current->comm, free);
+                printk(KERN_WARNING "%s (%d) used greatest stack depth: "
+                                "%lu bytes left\n",
+                                current->comm, task_pid_nr(current), free);
                 lowest_to_date = free;
         }
         spin_unlock(&low_water_lock);
@@ -946,12 +953,13 @@ void do_exit(long code)
         exit_signals(tsk);  /* sets PF_EXITING */
         /*
          * tsk->flags are checked in the futex code to protect against
-         * an exiting task cleaning up the robust pi futexes.
+         * an exiting task cleaning up the robust pi futexes, and in
+         * task_work_add() to avoid the race with exit_task_work().
          */
         smp_mb();
         raw_spin_unlock_wait(&tsk->pi_lock);
 
-        exit_irq_thread();
+        exit_task_work(tsk);
 
         if (unlikely(in_atomic()))
                 printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
@@ -1214,7 +1222,7 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
         unsigned long state;
         int retval, status, traced;
         pid_t pid = task_pid_vnr(p);
-        uid_t uid = __task_cred(p)->uid;
+        uid_t uid = from_kuid_munged(current_user_ns(), task_uid(p));
         struct siginfo __user *infop;
 
         if (!likely(wo->wo_flags & WEXITED))
@@ -1427,7 +1435,7 @@ static int wait_task_stopped(struct wait_opts *wo,
         if (!unlikely(wo->wo_flags & WNOWAIT))
                 *p_code = 0;
 
-        uid = task_uid(p);
+        uid = from_kuid_munged(current_user_ns(), task_uid(p));
 unlock_sig:
         spin_unlock_irq(&p->sighand->siglock);
         if (!exit_code)
@@ -1500,7 +1508,7 @@ static int wait_task_continued(struct wait_opts *wo, struct task_struct *p)
         }
         if (!unlikely(wo->wo_flags & WNOWAIT))
                 p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
-        uid = task_uid(p);
+        uid = from_kuid_munged(current_user_ns(), task_uid(p));
         spin_unlock_irq(&p->sighand->siglock);
 
         pid = task_pid_vnr(p);