diff --git a/include/linux/sched.h b/include/linux/sched.h
index 6e42ada26345d507ffdec856107382a9fb67656a..dee41bf59e6b8f7b2220d3fd28062cf6c5629395 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2139,6 +2139,9 @@ static inline void put_task_struct(struct task_struct *t)
 		__put_task_struct(t);
 }
 
+struct task_struct *task_rcu_dereference(struct task_struct **ptask);
+struct task_struct *try_get_task_struct(struct task_struct **ptask);
+
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
 extern void task_cputime(struct task_struct *t,
 			 cputime_t *utime, cputime_t *stime);
diff --git a/kernel/exit.c b/kernel/exit.c
index 9e6e1356e6bbc2dbb2aeb9ef5b2b02d05961ad3c..2fb4d44c51b1f9c06346d6885d056406dc7a6079 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -210,6 +210,82 @@ void release_task(struct task_struct *p)
 		goto repeat;
 }
 
+/*
+ * Note that if this function returns a valid task_struct pointer (!NULL)
+ * task->usage must remain >0 for the duration of the RCU critical section.
+ */
+struct task_struct *task_rcu_dereference(struct task_struct **ptask)
+{
+	struct sighand_struct *sighand;
+	struct task_struct *task;
+
+	/*
+	 * We need to verify that release_task() was not called and thus
+	 * delayed_put_task_struct() can't run and drop the last reference
+	 * before rcu_read_unlock(). We check task->sighand != NULL,
+	 * but we can read the already freed and reused memory.
+	 */
+retry:
+	task = rcu_dereference(*ptask);
+	if (!task)
+		return NULL;
+
+	probe_kernel_address(&task->sighand, sighand);
+
+	/*
+	 * Pairs with atomic_dec_and_test() in put_task_struct(). If this task
+	 * was already freed we can not miss the preceding update of this
+	 * pointer.
+	 */
+	smp_rmb();
+	if (unlikely(task != READ_ONCE(*ptask)))
+		goto retry;
+
+	/*
+	 * We've re-checked that "task == *ptask", now we have two different
+	 * cases:
+	 *
+	 * 1. This is actually the same task/task_struct. In this case
+	 *    sighand != NULL tells us it is still alive.
+	 *
+	 * 2. This is another task which got the same memory for task_struct.
+	 *    We can't know this of course, and we can not trust
+	 *    sighand != NULL.
+	 *
+	 *    In this case we actually return a random value, but this is
+	 *    correct.
+	 *
+	 *    If we return NULL - we can pretend that we actually noticed that
+	 *    *ptask was updated when the previous task has exited. Or pretend
+	 *    that probe_slab_address(&sighand) reads NULL.
+	 *
+	 *    If we return the new task (because sighand is not NULL for any
+	 *    reason) - this is fine too. This (new) task can't go away before
+	 *    another gp pass.
+	 *
+	 *    And note: We could even eliminate the false positive if re-read
+	 *    task->sighand once again to avoid the falsely NULL. But this case
+	 *    is very unlikely so we don't care.
+	 */
+	if (!sighand)
+		return NULL;
+
+	return task;
+}
+
+struct task_struct *try_get_task_struct(struct task_struct **ptask)
+{
+	struct task_struct *task;
+
+	rcu_read_lock();
+	task = task_rcu_dereference(ptask);
+	if (task)
+		get_task_struct(task);
+	rcu_read_unlock();
+
+	return task;
+}
+
 /*
  * Determine if a process group is "orphaned", according to the POSIX
  * definition in 2.2.2.52.  Orphaned process groups are not to be affected