[PATCH 5.15 740/779] tracing: Avoid -Warray-bounds warning for __rel_loc macro

From: Greg Kroah-Hartman
Date: Mon Aug 15 2022 - 15:57:21 EST


From: Masami Hiramatsu <mhiramat@xxxxxxxxxx>

[ Upstream commit 58c5724ec2cdd72b22107ec5de00d90cc4797796 ]

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.

Link: https://lkml.kernel.org/r/20220125233154.dac280ed36944c0c2fe6f3ac@xxxxxxxxxx

Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
[ This did not fix the warning, but is still a nice clean up ]
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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
--
2.35.1