diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 7e41ac5033adc4ecbaf7dd3aba22e53e93d0275f..ca588a3ac01bcbf8a44c5c3eae0de0914d473ea0 100755
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -925,6 +925,9 @@ unsigned long get_wchan(struct task_struct *p)
 	if (p == current || p->state == TASK_RUNNING)
 		return 0;
 
+	if (!try_get_task_stack(p))
+		return 0;
+
 	for (unwind_start(&state, p, NULL, NULL); !unwind_done(&state);
 	     unwind_next_frame(&state)) {
 	        addr = unwind_get_return_address(&state);
@@ -934,6 +937,8 @@ unsigned long get_wchan(struct task_struct *p)
 	                continue;
 	        break;
 	}
+ 
+	put_task_stack(p);
 
 	return addr;
 }