Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull stacktrace fix from Thomas Gleixner:
 "Fix yet another instance of kernel thread check which ignores that
  kernel threads can call use_mm()"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  stacktrace: Use PF_KTHREAD to check for kernel threads

kernel/stacktrace.c

@@ -228,7 +228,7 @@ unsigned int stack_trace_save_user(unsigned long *store, unsigned int size)
 	};
 
 	/* Trace user stack if not a kernel thread */
-	if (!current->mm)
+	if (current->flags & PF_KTHREAD)
 		return 0;
 
 	arch_stack_walk_user(consume_entry, &c, task_pt_regs(current));