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Commit 873c642f authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Steven Rostedt
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tracing: Clear all trace buffers when unloaded module event was used 



Currently we do not know what buffer a module event was enabled in.
On unload, it is safest to clear all buffer instances, not just the
top level buffer.

Todo: Clear only the buffer that the event was used in. The
infrastructure is there to do this, but it makes the code a bit
more complex. Lets get the current code vetted before we add that.

Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 575380da

kernel/trace/trace.c

+8 −2
Original line number Diff line number Diff line
@@ -912,9 +912,15 @@ void tracing_reset_current(int cpu) 
	tracing_reset(&global_trace, cpu);

}



void tracing_reset_current_online_cpus(void)

void tracing_reset_all_online_cpus(void)

{

	tracing_reset_online_cpus(&global_trace);

	struct trace_array *tr;



	mutex_lock(&trace_types_lock);

	list_for_each_entry(tr, &ftrace_trace_arrays, list) {

		tracing_reset_online_cpus(tr);

	}

	mutex_unlock(&trace_types_lock);

}



#define SAVED_CMDLINES 128

kernel/trace/trace.h

+1 −1
Original line number Diff line number Diff line
@@ -496,7 +496,7 @@ int tracing_is_enabled(void); 
void tracing_reset(struct trace_array *tr, int cpu);

void tracing_reset_online_cpus(struct trace_array *tr);

void tracing_reset_current(int cpu);

void tracing_reset_current_online_cpus(void);

void tracing_reset_all_online_cpus(void);

int tracing_open_generic(struct inode *inode, struct file *filp);

struct dentry *trace_create_file(const char *name,

				 umode_t mode,

kernel/trace/trace_events.c

+7 −3
Original line number Diff line number Diff line
@@ -1649,14 +1649,18 @@ static void trace_module_remove_events(struct module *mod) 
		list_del(&file_ops->list);

		kfree(file_ops);

	}

	up_write(&trace_event_mutex);



	/*

	 * It is safest to reset the ring buffer if the module being unloaded

	 * registered any events that were used.

	 * registered any events that were used. The only worry is if

	 * a new module gets loaded, and takes on the same id as the events

	 * of this module. When printing out the buffer, traced events left

	 * over from this module may be passed to the new module events and

	 * unexpected results may occur.

	 */

	if (clear_trace)

		tracing_reset_current_online_cpus();

	up_write(&trace_event_mutex);

		tracing_reset_all_online_cpus();

}



static int trace_module_notify(struct notifier_block *self,