linux/include/trace/perf.h
Kees Cook c6d777acdf 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 <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Fixes: 55de2c0b56 ("tracing: Add '__rel_loc' using trace event macros")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-01-27 19:15:45 -05:00

109 lines
3.1 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#undef TRACE_SYSTEM_VAR
#ifdef CONFIG_PERF_EVENTS
#undef __entry
#define __entry entry
#undef __get_dynamic_array
#define __get_dynamic_array(field) \
((void *)__entry + (__entry->__data_loc_##field & 0xffff))
#undef __get_dynamic_array_len
#define __get_dynamic_array_len(field) \
((__entry->__data_loc_##field >> 16) & 0xffff)
#undef __get_str
#define __get_str(field) ((char *)__get_dynamic_array(field))
#undef __get_bitmask
#define __get_bitmask(field) (char *)__get_dynamic_array(field)
#undef __get_rel_dynamic_array
#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
#define __get_rel_dynamic_array_len(field) \
((__entry->__rel_loc_##field >> 16) & 0xffff)
#undef __get_rel_str
#define __get_rel_str(field) ((char *)__get_rel_dynamic_array(field))
#undef __get_rel_bitmask
#define __get_rel_bitmask(field) (char *)__get_rel_dynamic_array(field)
#undef __perf_count
#define __perf_count(c) (__count = (c))
#undef __perf_task
#define __perf_task(t) (__task = (t))
#undef DECLARE_EVENT_CLASS
#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print) \
static notrace void \
perf_trace_##call(void *__data, proto) \
{ \
struct trace_event_call *event_call = __data; \
struct trace_event_data_offsets_##call __maybe_unused __data_offsets;\
struct trace_event_raw_##call *entry; \
struct pt_regs *__regs; \
u64 __count = 1; \
struct task_struct *__task = NULL; \
struct hlist_head *head; \
int __entry_size; \
int __data_size; \
int rctx; \
\
__data_size = trace_event_get_offsets_##call(&__data_offsets, args); \
\
head = this_cpu_ptr(event_call->perf_events); \
if (!bpf_prog_array_valid(event_call) && \
__builtin_constant_p(!__task) && !__task && \
hlist_empty(head)) \
return; \
\
__entry_size = ALIGN(__data_size + sizeof(*entry) + sizeof(u32),\
sizeof(u64)); \
__entry_size -= sizeof(u32); \
\
entry = perf_trace_buf_alloc(__entry_size, &__regs, &rctx); \
if (!entry) \
return; \
\
perf_fetch_caller_regs(__regs); \
\
tstruct \
\
{ assign; } \
\
perf_trace_run_bpf_submit(entry, __entry_size, rctx, \
event_call, __count, __regs, \
head, __task); \
}
/*
* This part is compiled out, it is only here as a build time check
* to make sure that if the tracepoint handling changes, the
* perf probe will fail to compile unless it too is updated.
*/
#undef DEFINE_EVENT
#define DEFINE_EVENT(template, call, proto, args) \
static inline void perf_test_probe_##call(void) \
{ \
check_trace_callback_type_##call(perf_trace_##template); \
}
#undef DEFINE_EVENT_PRINT
#define DEFINE_EVENT_PRINT(template, name, proto, args, print) \
DEFINE_EVENT(template, name, PARAMS(proto), PARAMS(args))
#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
#endif /* CONFIG_PERF_EVENTS */