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authorZiqian SUN (Zamir) <zsun@redhat.com>2017-09-11 14:26:35 +0800
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2017-09-19 12:36:01 -0400
commitc7b3ae0bd2ca658c7a71c49901d08c590294fac9 (patch)
tree6e33bb7c8a1a01d7c63b513129b1097d1ba73ae6 /kernel
parent8dd33bcb7050dd6f8c1432732f930932c9d3a33e (diff)
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: Ziqian SUN (Zamir) <zsun@redhat.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace.c7
-rw-r--r--kernel/trace/trace.h2
-rw-r--r--kernel/trace/trace_mmiotrace.c1
3 files changed, 10 insertions, 0 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index a7fb136da891..d3ca35f38803 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -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;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index fb5d54d0d1b3..652c682707cd 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -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;
};
diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c
index cd7480d0a201..dca78fc48439 100644
--- a/kernel/trace/trace_mmiotrace.c
+++ b/kernel/trace/trace_mmiotrace.c
@@ -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)