In event format strings, the array size is reported in two locations.
One in array subscript and then via the "size:" attribute. The values
reported there have a mismatch.
For e.g., in sched:sched_switch the prev_comm and next_comm character
arrays have subscript values as [32] where as the actual field size is
16.
name: sched_switch
ID: 301
format:
field:unsigned short common_type; offset:0; size:2;
signed:0;
field:unsigned char common_flags; offset:2; size:1;
signed:0;
field:unsigned char common_preempt_count; offset:3;
size:1;signed:0;
field:int common_pid; offset:4; size:4; signed:1;
field:char prev_comm[32]; offset:8; size:16;
signed:1;
field:pid_t prev_pid; offset:24; size:4; signed:1;
field:int prev_prio; offset:28; size:4; signed:1;
field:long prev_state; offset:32; size:8; signed:1;
field:char next_comm[32]; offset:40; size:16;
signed:1;
field:pid_t next_pid; offset:56; size:4; signed:1;
field:int next_prio; offset:60; size:4; signed:1;
After bisection, the following commit was blamed:
92edca0 tracing: Use direct field, type and system names
This commit removes the duplication of strings for field->name and
field->type assuming that all the strings passed in
__trace_define_field() are immutable. This is not true for arrays, where
the type string is created in event_storage variable and field->type for
all array fields points to event_storage.
Use __stringify() to create a string constant for the type string.
Also, get rid of event_storage and event_storage_mutex that are not
needed anymore.
Signed-off-by: Vaibhav Nagarnaik <vnagarn...@google.com>
---
* Fix warning from previous version about mixed declarations.
include/linux/ftrace_event.h | 4 ----
include/trace/ftrace.h | 7 ++-----
kernel/trace/trace_events.c | 6 ------
kernel/trace/trace_export.c | 7 ++-----
4 files changed, 4 insertions(+), 20 deletions(-)
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 4e4cc28..4cdb3a1 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -495,10 +495,6 @@ enum {
FILTER_TRACE_FN,
};
-#define EVENT_STORAGE_SIZE 128
-extern struct mutex event_storage_mutex;
-extern char event_storage[EVENT_STORAGE_SIZE];
-
extern int trace_event_raw_init(struct ftrace_event_call *call);
extern int trace_define_field(struct ftrace_event_call *call, const char *type,
const char *name, int offset, int size,
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 1a8b28d..1ee19a2 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -310,15 +310,12 @@ static struct trace_event_functions
ftrace_event_type_funcs_##call = { \
#undef __array
#define __array(type, item, len) \
do { \
- mutex_lock(&event_storage_mutex); \
+ char *type_str = #type"["__stringify(len)"]"; \
BUILD_BUG_ON(len > MAX_FILTER_STR_VAL); \
- snprintf(event_storage, sizeof(event_storage), \
- "%s[%d]", #type, len); \
- ret = trace_define_field(event_call, event_storage, #item, \
+ ret = trace_define_field(event_call, type_str, #item, \
offsetof(typeof(field), item), \
sizeof(field.item), \
is_signed_type(type), FILTER_OTHER); \
- mutex_unlock(&event_storage_mutex); \
if (ret) \
return ret; \
} while (0);
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index e71ffd4..22826c7 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -27,12 +27,6 @@
DEFINE_MUTEX(event_mutex);
-DEFINE_MUTEX(event_storage_mutex);
-EXPORT_SYMBOL_GPL(event_storage_mutex);
-
-char event_storage[EVENT_STORAGE_SIZE];
-EXPORT_SYMBOL_GPL(event_storage);
-
LIST_HEAD(ftrace_events);
static LIST_HEAD(ftrace_common_fields);
diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c
index 7c3e3e7..ee0a509 100644
--- a/kernel/trace/trace_export.c
+++ b/kernel/trace/trace_export.c
@@ -95,15 +95,12 @@ static void __always_unused ____ftrace_check_##name(void)
\
#undef __array
#define __array(type, item, len) \
do { \
+ char *type_str = #type"["__stringify(len)"]"; \
BUILD_BUG_ON(len > MAX_FILTER_STR_VAL); \
- mutex_lock(&event_storage_mutex); \
- snprintf(event_storage, sizeof(event_storage), \
- "%s[%d]", #type, len); \
- ret = trace_define_field(event_call, event_storage, #item, \
+ ret = trace_define_field(event_call, type_str, #item, \
offsetof(typeof(field), item), \
sizeof(field.item), \
is_signed_type(type), filter_type); \
- mutex_unlock(&event_storage_mutex); \
if (ret) \
return ret; \
} while (0);
--
1.9.0.rc1.175.g0b1dcb5
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