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ftrace: Do not run selftest if command line parameter is set

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If the kernel command line ftrace filter parameters are set
(ftrace_filter or ftrace_notrace), force the function self test to
pass, with a warning why it was forced.

If the user adds a filter to the kernel command line, it is assumed
that they know what they are doing, and the self test should just not
run instead of failing (which disables function tracing) or clearing
the filter, as that will probably annoy the user.

If the user wants the selftest to run, the message will tell them why
it did not.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Red Hat) 2013-06-27 22:18:06 -04:00 committed by Steven Rostedt
parent cf6735a4b1
commit f1ed7c741f
3 changed files with 22 additions and 2 deletions
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5
kernel/trace/ftrace.c
View File

@ -3537,8 +3537,12 @@ EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
/* Used by function selftest to not test if filter is set */
bool ftrace_filter_param __initdata;
static int __init set_ftrace_notrace(char *str)
{
ftrace_filter_param = true;
strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
return 1;
}
@ -3546,6 +3550,7 @@ __setup("ftrace_notrace=", set_ftrace_notrace);
static int __init set_ftrace_filter(char *str)
{
ftrace_filter_param = true;
strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
return 1;
}

1
kernel/trace/trace.h
View File

@ -776,6 +776,7 @@ print_graph_function_flags(struct trace_iterator *iter, u32 flags)
extern struct list_head ftrace_pids;
#ifdef CONFIG_FUNCTION_TRACER
extern bool ftrace_filter_param __initdata;
static inline int ftrace_trace_task(struct task_struct *task)
{
if (list_empty(&ftrace_pids))

18
kernel/trace/trace_selftest.c
View File

@ -640,13 +640,20 @@ out:
* Enable ftrace, sleep 1/10 second, and then read the trace
* buffer to see if all is in order.
*/
int
__init int
trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr)
{
int save_ftrace_enabled = ftrace_enabled;
unsigned long count;
int ret;
#ifdef CONFIG_DYNAMIC_FTRACE
if (ftrace_filter_param) {
printk(KERN_CONT " ... kernel command line filter set: force PASS ... ");
return 0;
}
#endif
/* make sure msleep has been recorded */
msleep(1);
@ -727,13 +734,20 @@ static int trace_graph_entry_watchdog(struct ftrace_graph_ent *trace)
* Pretty much the same than for the function tracer from which the selftest
* has been borrowed.
*/
int
__init int
trace_selftest_startup_function_graph(struct tracer *trace,
struct trace_array *tr)
{
int ret;
unsigned long count;
#ifdef CONFIG_DYNAMIC_FTRACE
if (ftrace_filter_param) {
printk(KERN_CONT " ... kernel command line filter set: force PASS ... ");
return 0;
}
#endif
/*
* Simulate the init() callback but we attach a watchdog callback
* to detect and recover from possible hangs