tracing: Ignore mmiotrace from kernel commandline (c7b3ae0b) · Commits · 戴 / test

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:

Ziqian SUN (Zamir) <zsun@redhat.com> Signed-off-by:

Steven Rostedt (VMware) <rostedt@goodmis.org>

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)

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