Merge branch 'akpm' (Andrew's patch-bomb)

* emailed from Andrew Morton <akpm@linux-foundation.org>: (21 patches)
  mm/memblock: fix overlapping allocation when doubling reserved array
  c/r: prctl: Move PR_GET_TID_ADDRESS to a proper place
  pidns: find_new_reaper() can no longer switch to init_pid_ns.child_reaper
  pidns: guarantee that the pidns init will be the last pidns process reaped
  fault-inject: avoid call to random32() if fault injection is disabled
  Viresh has moved
  get_maintainer: Fix --help warning
  mm/memory.c: fix kernel-doc warnings
  mm: fix kernel-doc warnings
  mm: correctly synchronize rss-counters at exit/exec
  mm, thp: print useful information when mmap_sem is unlocked in zap_pmd_range
  h8300: use the declarations provided by <asm/sections.h>
  h8300: fix use of extinct _sbss and _ebss
  xtensa: use the declarations provided by <asm/sections.h>
  xtensa: use "test -e" instead of bashism "test -a"
  xtensa: replace xtensa-specific _f{data,text} by _s{data,text}
  memcg: fix use_hierarchy css_is_ancestor oops regression
  mm, oom: fix and cleanup oom score calculations
  nilfs2: ensure proper cache clearing for gc-inodes
  thp: avoid atomic64_read in pmd_read_atomic for 32bit PAE
  ...

1 files changed, 20 insertions, 0 deletions

diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 16b20e38c4a1..b3c7fd554250 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -184,11 +184,31 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns)
 	}
 	read_unlock(&tasklist_lock);
 
+	/* Firstly reap the EXIT_ZOMBIE children we may have. */
 	do {
 		clear_thread_flag(TIF_SIGPENDING);
 		rc = sys_wait4(-1, NULL, __WALL, NULL);
 	} while (rc != -ECHILD);
 
+	/*
+	 * sys_wait4() above can't reap the TASK_DEAD children.
+	 * Make sure they all go away, see __unhash_process().
+	 */
+	for (;;) {
+		bool need_wait = false;
+
+		read_lock(&tasklist_lock);
+		if (!list_empty(&current->children)) {
+			__set_current_state(TASK_UNINTERRUPTIBLE);
+			need_wait = true;
+		}
+		read_unlock(&tasklist_lock);
+
+		if (!need_wait)
+			break;
+		schedule();
+	}
+
 	if (pid_ns->reboot)
 		current->signal->group_exit_code = pid_ns->reboot;