xtensa: fix return_address

jcmvbkbc · jcmvbkbc · commit ada770b1e74a · 2019-04-04T11:18:55.000-07:00
return_address returns the address that is one level higher in the call
stack than requested in its argument, because level 0 corresponds to its
caller's return address. Use requested level as the number of stack
frames to skip.

This fixes the address reported by might_sleep and friends.

Cc: stable@vger.kernel.org
Signed-off-by: Max Filippov &lt;jcmvbkbc@gmail.com&gt;
diff --git a/arch/xtensa/kernel/stacktrace.c b/arch/xtensa/kernel/stacktrace.c
@@ -253,10 +253,14 @@ static int return_address_cb(struct stackframe *frame, void *data)
 	return 1;
 }
 
+/*
+ * level == 0 is for the return address from the caller of this function,
+ * not from this function itself.
+ */
 unsigned long return_address(unsigned level)
 {
 	struct return_addr_data r = {
-		.skip = level + 1,
+		.skip = level,
 	};
 	walk_stackframe(stack_pointer(NULL), return_address_cb, &r);
 	return r.addr;
