From c6d777acdf8f62d4ebaef0e5c6cd8fedbd6e8546 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 25 Jan 2022 14:00:37 -0800 Subject: [PATCH] tracing/perf: Avoid -Warray-bounds warning for __rel_loc macro As done for trace_events.h, also fix the __rel_loc macro in perf.h, which silences the -Warray-bounds warning: In file included from ./include/linux/string.h:253, from ./include/linux/bitmap.h:11, from ./include/linux/cpumask.h:12, from ./include/linux/mm_types_task.h:14, from ./include/linux/mm_types.h:5, from ./include/linux/buildid.h:5, from ./include/linux/module.h:14, from samples/trace_events/trace-events-sample.c:2: In function '__fortify_strcpy', inlined from 'perf_trace_foo_rel_loc' at samples/trace_events/./trace-events-sample.h:519:1: ./include/linux/fortify-string.h:47:33: warning: '__builtin_strcpy' offset 12 is out of the bounds [ 0, 4] [-Warray-bounds] 47 | #define __underlying_strcpy __builtin_strcpy | ^ ./include/linux/fortify-string.h:445:24: note: in expansion of macro '__underlying_strcpy' 445 | return __underlying_strcpy(p, q); | ^~~~~~~~~~~~~~~~~~~ Also make __data struct member a proper flexible array to avoid future problems. Link: https://lkml.kernel.org/r/20220125220037.2738923-1-keescook@chromium.org Cc: Steven Rostedt Cc: Masami Hiramatsu Fixes: 55de2c0b5610c ("tracing: Add '__rel_loc' using trace event macros") Reported-by: Stephen Rothwell Signed-off-by: Kees Cook Signed-off-by: Steven Rostedt (Google) --- include/trace/perf.h | 5 +++-- include/trace/trace_events.h | 2 +- 2 files changed, 4 insertions(+), 3 deletions(-) diff --git a/include/trace/perf.h b/include/trace/perf.h index ea4405de175a3e..5d48c46a300835 100644 --- a/include/trace/perf.h +++ b/include/trace/perf.h @@ -23,8 +23,9 @@ #undef __get_rel_dynamic_array #define __get_rel_dynamic_array(field) \ - ((void *)(&__entry->__rel_loc_##field) + \ - sizeof(__entry->__rel_loc_##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 diff --git a/include/trace/trace_events.h b/include/trace/trace_events.h index 65d927e059d31d..3d29919045af2e 100644 --- a/include/trace/trace_events.h +++ b/include/trace/trace_events.h @@ -128,7 +128,7 @@ TRACE_MAKE_SYSTEM_STR(); struct trace_event_raw_##name { \ struct trace_entry ent; \ tstruct \ - char __data[0]; \ + char __data[]; \ }; \ \ static struct trace_event_class event_class_##name;