signal: break out of wait loops on kthread_stop()

This is a small tweak to kthread_stop so it breaks out of
 interruptible waits, that don't explicitly test for kthread_stop.
 These interruptible waits occassionaly occur in kernel threads do to
 code sharing.
 
 Jason A. Donenfeld (1):
       signal: break out of wait loops on kthread_stop()
 
  kernel/kthread.c | 1 +
  1 file changed, 1 insertion(+)
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Merge tag 'interrupting_kthread_stop-for-v5.20' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull kthread update from Eric Biederman:
 "Break out of wait loops on kthread_stop()

  This is a small tweak to kthread_stop so it breaks out of
  interruptible waits, that don't explicitly test for kthread_stop.

  These interruptible waits occassionaly occur in kernel threads do to
  code sharing"

* tag 'interrupting_kthread_stop-for-v5.20' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  signal: break out of wait loops on kthread_stop()

kernel/kthread.c

@@ -704,6 +704,7 @@ int kthread_stop(struct task_struct *k)
 	kthread = to_kthread(k);
 	set_bit(KTHREAD_SHOULD_STOP, &kthread->flags);
 	kthread_unpark(k);
+	set_tsk_thread_flag(k, TIF_NOTIFY_SIGNAL);
 	wake_up_process(k);
 	wait_for_completion(&kthread->exited);
 	ret = kthread->result;