Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull proc fix from Eric Biederman:
 "While running syzbot happened to spot one more oversight in my rework
  of proc_flush_task.

  The fields proc_self and proc_thread_self were not being reinitialized
  when proc was unmounted, which could cause problems if the mount of
  proc fails"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  proc: Handle umounts cleanly

Author: torvalds

fs/proc/root.c

@@ -196,6 +196,13 @@ static void proc_kill_sb(struct super_block *sb)
 	if (ns->proc_thread_self)
 		dput(ns->proc_thread_self);
 	kill_anon_super(sb);
+
+	/* Make the pid namespace safe for the next mount of proc */
+	ns->proc_self = NULL;
+	ns->proc_thread_self = NULL;
+	ns->pid_gid = GLOBAL_ROOT_GID;
+	ns->hide_pid = 0;
+
 	put_pid_ns(ns);
 }