From f1ed7c741fcd0c3d7d318e7c19813d89934b9296 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Thu, 27 Jun 2013 22:18:06 -0400 Subject: [PATCH] ftrace: Do not run selftest if command line parameter is set 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 --- kernel/trace/ftrace.c | 5 +++++ kernel/trace/trace.h | 1 + kernel/trace/trace_selftest.c | 18 ++++++++++++++++-- 3 files changed, 22 insertions(+), 2 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 26e19105cdcc..67708f46baae 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -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; } diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 711ca7d3e7f1..a88939e666b7 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -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)) diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index 2901e3b88590..a7329b7902f8 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -640,13 +640,20 @@ trace_selftest_function_regs(void) * 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