[PATCH] tracing: Avoid -Warray-bounds warning for __rel_loc macro

[Masami Hiramatsu]

Since -Warray-bounds checks the destination size from the
type of given pointer, __assign_rel_str() macro gets warned
because it passes the pointer to the 'u32' field instead of
'trace_event_raw_*' data structure.
Pass the data address calculated from the 'trace_event_raw_*'
instead of 'u32' __rel_loc field.

Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
---
 include/trace/trace_events.h | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/include/trace/trace_events.h b/include/trace/trace_events.h
index 8c6f7c433518..65d927e059d3 100644
--- a/include/trace/trace_events.h
+++ b/include/trace/trace_events.h
@@ -318,9 +318,10 @@ TRACE_MAKE_SYSTEM_STR();
 #define __get_str(field) ((char *)__get_dynamic_array(field))
 
 #undef __get_rel_dynamic_array
-#define __get_rel_dynamic_array(field)	\
-		((void *)(&__entry->__rel_loc_##field) +	\
-		 sizeof(__entry->__rel_loc_##field) +		\
+#define __get_rel_dynamic_array(field)					\
+		((void *)__entry + 					\
+		 offsetof(typeof(*__entry), __rel_loc_##field) +	\
+		 sizeof(__entry->__rel_loc_##field) +			\
 		 (__entry->__rel_loc_##field & 0xffff))
 
 #undef __get_rel_dynamic_array_len
-- 
2.25.1


-- 
Masami Hiramatsu <mhiramat@xxxxxxxxxx>