From: "Steven Rostedt (Google)" <rost...@goodmis.org>
The TRACE_EVENT() macro handles dynamic strings by having:
TP_PROTO(struct some_struct *s),
TP_ARGS(s),
TP_STRUCT__entry(
__string(my_string, s->string)
),
TP_fast_assign(
__assign_str(my_string, s->string);
)
TP_printk("%s", __get_str(my_string))
There's even some code that may call a function helper to find the
s->string value. The problem with the above is that the work to get the
length of s->string is done twice. Once at the __string() and again in the
__assign_str().
The length of the string is calculated via a strlen(), not once, but twice
(via strcpy() in __assign_str()). Once during the __string() macro and again
in __assign_str(). But the length is actually already recorded in the data
location and there's no reason to call strlen() again.
Just use the saved length that was saved in the __string() code for the
__assign_str() code.
Signed-off-by: Steven Rostedt (Google) <rost...@goodmis.org>
---
include/trace/stages/stage6_event_callback.h | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/include/trace/stages/stage6_event_callback.h
b/include/trace/stages/stage6_event_callback.h
index e09e3d019dcc..d389725937e9 100644
--- a/include/trace/stages/stage6_event_callback.h
+++ b/include/trace/stages/stage6_event_callback.h
@@ -32,8 +32,9 @@
#undef __assign_str
#define __assign_str(dst, src) \
- strcpy(__get_str(dst), __data_offsets.dst##_ptr_ ? \
- __data_offsets.dst##_ptr_ : "(null)")
+ memcpy(__get_str(dst), __data_offsets.dst##_ptr_ ? \
+ __data_offsets.dst##_ptr_ : "(null)", \
+ __get_dynamic_array_len(dst))
#undef __assign_str_len
#define __assign_str_len(dst, src, len)
\
@@ -94,8 +95,9 @@
#undef __assign_rel_str
#define __assign_rel_str(dst, src) \
- strcpy(__get_rel_str(dst), __data_offsets.dst##_ptr_ ? \
- __data_offsets.dst##_ptr_ : "(null)")
+ memcpy(__get_rel_str(dst), __data_offsets.dst##_ptr_ ? \
+ __data_offsets.dst##_ptr_ : "(null)", \
+ __get_rel_dynamic_array_len(dst))
#undef __assign_rel_str_len
#define __assign_rel_str_len(dst, src, len) \
--
2.43.0
