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tracing/boot: Initialize per-instance event list in early boot 

Initialize per-instance event list in early boot time (before
initializing instance directory on tracefs). This fixes boot-time
tracing to correctly handle the boot-time per-instance settings.

Link: https://lkml.kernel.org/r/160096560826.182763.17110991546046128881.stgit@devnote2

Fixes: 4114fbfd02 ("tracing: Enable creating new instance early boot")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Masami Hiramatsu 2020-09-25 01:40:08 +09:00 committed by Steven Rostedt (VMware)
parent fd264ce96c
commit 720dee53ad
3 changed files with 19 additions and 15 deletions
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3
kernel/trace/trace.c
View File

@ -8700,7 +8700,8 @@ static struct trace_array *trace_array_create(const char *name)
ret = trace_array_create_dir(tr);
if (ret)
goto out_free_tr;
}
} else
__trace_early_add_events(tr);
list_add(&tr->list, &ftrace_trace_arrays);

1
kernel/trace/trace.h
View File

@ -1658,6 +1658,7 @@ extern void trace_event_enable_tgid_record(bool enable);
extern int event_trace_init(void);
extern int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr);
extern int event_trace_del_tracer(struct trace_array *tr);
extern void __trace_early_add_events(struct trace_array *tr);
extern struct trace_event_file *__find_event_file(struct trace_array *tr,
const char *system,

30
kernel/trace/trace_events.c
View File

@ -3131,14 +3131,13 @@ static inline int register_event_cmds(void) { return 0; }
#endif /* CONFIG_DYNAMIC_FTRACE */
/*
* The top level array has already had its trace_event_file
* descriptors created in order to allow for early events to
* be recorded. This function is called after the tracefs has been
* initialized, and we now have to create the files associated
* to the events.
* The top level array and trace arrays created by boot-time tracing
* have already had its trace_event_file descriptors created in order
* to allow for early events to be recorded.
* This function is called after the tracefs has been initialized,
* and we now have to create the files associated to the events.
*/
static __init void
__trace_early_add_event_dirs(struct trace_array *tr)
static void __trace_early_add_event_dirs(struct trace_array *tr)
{
struct trace_event_file *file;
int ret;
@ -3153,13 +3152,12 @@ __trace_early_add_event_dirs(struct trace_array *tr)
}
/*
* For early boot up, the top trace array requires to have
* a list of events that can be enabled. This must be done before
* the filesystem is set up in order to allow events to be traced
* early.
* For early boot up, the top trace array and the trace arrays created
* by boot-time tracing require to have a list of events that can be
* enabled. This must be done before the filesystem is set up in order
* to allow events to be traced early.
*/
static __init void
__trace_early_add_events(struct trace_array *tr)
void __trace_early_add_events(struct trace_array *tr)
{
struct trace_event_call *call;
int ret;
@ -3290,7 +3288,11 @@ int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr)
goto out;
down_write(&trace_event_sem);
__trace_add_event_dirs(tr);
/* If tr already has the event list, it is initialized in early boot. */
if (unlikely(!list_empty(&tr->events)))
__trace_early_add_event_dirs(tr);
else
__trace_add_event_dirs(tr);
up_write(&trace_event_sem);
out: