1 files changed, 28 insertions, 8 deletions

diff --git a/arch/s390/kernel/dumpstack.c b/arch/s390/kernel/dumpstack.c
index 1b6081c0aff9..6693383bc01b 100644
--- a/arch/s390/kernel/dumpstack.c
+++ b/arch/s390/kernel/dumpstack.c
@@ -78,17 +78,37 @@ void dump_trace(dump_trace_func_t func, void *data, struct task_struct *task,
 	sp = __dump_trace(func, data, sp,
 			  S390_lowcore.async_stack + frame_size - ASYNC_SIZE,
 			  S390_lowcore.async_stack + frame_size);
-	if (task)
-		__dump_trace(func, data, sp,
-			     (unsigned long)task_stack_page(task),
-			     (unsigned long)task_stack_page(task) + THREAD_SIZE);
-	else
-		__dump_trace(func, data, sp,
-			     S390_lowcore.thread_info,
-			     S390_lowcore.thread_info + THREAD_SIZE);
+	task = task ?: current;
+	__dump_trace(func, data, sp,
+		     (unsigned long)task_stack_page(task),
+		     (unsigned long)task_stack_page(task) + THREAD_SIZE);
 }
 EXPORT_SYMBOL_GPL(dump_trace);
 
+struct return_address_data {
+	unsigned long address;
+	int depth;
+};
+
+static int __return_address(void *data, unsigned long address)
+{
+	struct return_address_data *rd = data;
+
+	if (rd->depth--)
+		return 0;
+	rd->address = address;
+	return 1;
+}
+
+unsigned long return_address(int depth)
+{
+	struct return_address_data rd = { .depth = depth + 2 };
+
+	dump_trace(__return_address, &rd, NULL, current_stack_pointer());
+	return rd.address;
+}
+EXPORT_SYMBOL_GPL(return_address);
+
 static int show_address(void *data, unsigned long address)
 {
 	printk("([<%016lx>] %pSR)\n", address, (void *)address);