lib: add sanity checks to list_del operation

libos-nuse · Mar 2, 2015 · 793e2d6 · 793e2d6
1 parent 51bb4f9
commit 793e2d6
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Showing 4 changed files with 32 additions and 16 deletions.
diff --git a/arch/lib/nuse.c b/arch/lib/nuse.c
@@ -232,6 +232,8 @@ void nuse_event_cancel(struct SimKernel *kernel, void *event)
 
 	nuse_fiber_stop(task->private);
 	/*  nuse_fiber_free (task->private); */
+	if (task->head.prev == LIST_POISON2)
+		return;
 	list_del_rcu(&task->head);
 }
 

diff --git a/arch/lib/sched.c b/arch/lib/sched.c
@@ -135,7 +135,8 @@ void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait)
 }
 void remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait)
 {
-	list_del(&wait->task_list);
+	if (wait->task_list.prev != LIST_POISON2)
+		list_del(&wait->task_list);
 }
 void
 prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state)
@@ -167,8 +168,9 @@ int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync,
 {
 	int ret = default_wake_function(wait, mode, sync, key);
 
-	if (ret)
+	if (ret && (wait->task_list.prev != LIST_POISON2)) {
 		list_del_init(&wait->task_list);
+	}
 	return ret;
 }
 
@@ -208,7 +210,9 @@ unsigned long wait_for_completion_timeout(struct completion *x,
 		do
 			timeout = schedule_timeout(timeout);
 		while (!x->done && timeout);
-		list_del(&wait.task_list);
+		if (wait.task_list.prev != LIST_POISON2) {
+			list_del(&wait.task_list);
+		}
 		if (!x->done)
 			return timeout;
 	}

diff --git a/arch/lib/timer.c b/arch/lib/timer.c
@@ -56,9 +56,11 @@ static void run_timer_softirq(struct softirq_action *h)
 		fn = timer->function;
 		data = timer->data;
 		lib_assert(timer->base == 0);
-		list_del(&timer->entry);
-		timer->entry.next = NULL;
-		fn(data);
+		if (timer->entry.prev != LIST_POISON2) {
+			list_del(&timer->entry);
+			timer->entry.next = NULL;
+			fn(data);
+		}
 	}
 }
 
@@ -78,7 +80,9 @@ static void timer_trampoline(void *context)
 	ensure_softirq_opened();
 	timer = context;
 	timer->base = 0;
-	list_del(&timer->entry);
+	if (timer->entry.prev != LIST_POISON2) {
+		list_del(&timer->entry);
+	}
 	list_add_tail(&timer->entry, &g_expired_events);
 	raise_softirq(TIMER_SOFTIRQ);
 }
@@ -136,8 +140,10 @@ int del_timer(struct timer_list *timer)
 		retval = 1;
 	} else
 		retval = 0;
-	list_del(&timer->entry);
-	timer->entry.next = NULL;
+	if (timer->entry.prev != LIST_POISON2) {
+		list_del(&timer->entry);
+		timer->entry.next = NULL;
+	}
 	return retval;
 }
 

diff --git a/arch/lib/workqueue.c b/arch/lib/workqueue.c
@@ -59,10 +59,12 @@ workqueue_function(void *context)
 						entry);
 			work_func_t f = work->func;
 
-			list_del_init(&work->entry);
-			clear_bit(WORK_STRUCT_PENDING_BIT,
-				  work_data_bits(work));
-			f(work);
+			if (work->entry.prev != LIST_POISON2) {
+				list_del_init(&work->entry);
+				clear_bit(WORK_STRUCT_PENDING_BIT,
+					  work_data_bits(work));
+				f(work);
+			}
 		}
 	}
 }
@@ -134,9 +136,11 @@ bool cancel_work_sync(struct work_struct *work)
 		return 0;
 	if (!list_empty(&work->entry)) {
 		/* work was queued. now unqueued. */
-		list_del_init(&work->entry);
-		clear_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work));
-		retval = 1;
+		if (work->entry.prev != LIST_POISON2) {
+			list_del_init(&work->entry);
+			clear_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work));
+			retval = 1;
+		}
 	}
 	return retval;
 }