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Commit c7b3ae0b authored by Ziqian SUN (Zamir)'s avatar Ziqian SUN (Zamir) Committed by Steven Rostedt (VMware)
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tracing: Ignore mmiotrace from kernel commandline 

The mmiotrace tracer cannot be enabled with ftrace=mmiotrace in kernel
commandline. With this patch, noboot is added to the tracer struct,
and when system boot with a tracer that has noboot=true, it will print
out a warning message and continue booting.

Link: http://lkml.kernel.org/r/1505111195-31942-1-git-send-email-zsun@redhat.com



Signed-off-by: default avatarZiqian SUN (Zamir) <zsun@redhat.com>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 8dd33bcb

kernel/trace/trace.c

+7 −0
Original line number Diff line number Diff line
@@ -5364,6 +5364,13 @@ static int tracing_set_tracer(struct trace_array *tr, const char *buf) 
	if (t == tr->current_trace)

		goto out;



	/* Some tracers won't work on kernel command line */

	if (system_state < SYSTEM_RUNNING && t->noboot) {

		pr_warn("Tracer '%s' is not allowed on command line, ignored\n",

			t->name);

		goto out;

	}



	/* Some tracers are only allowed for the top level buffer */

	if (!trace_ok_for_array(t, tr)) {

		ret = -EINVAL;

kernel/trace/trace.h

+2 −0
Original line number Diff line number Diff line
@@ -444,6 +444,8 @@ struct tracer { 
#ifdef CONFIG_TRACER_MAX_TRACE

	bool			use_max_tr;

#endif

	/* True if tracer cannot be enabled in kernel param */

	bool			noboot;

};

kernel/trace/trace_mmiotrace.c

+1 −0
Original line number Diff line number Diff line
@@ -282,6 +282,7 @@ static struct tracer mmio_tracer __read_mostly = 
	.close		= mmio_close,

	.read		= mmio_read,

	.print_line	= mmio_print_line,

	.noboot		= true,

};



__init static int init_mmio_trace(void)