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Commit 23aaa3c1 authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Steven Rostedt
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tracing: Fix leak of ring buffer data when new instances creation fails 

Yoshihiro Yunomae reported that the ring buffer data for a trace
instance does not get properly cleaned up when it fails. He proposed
a patch that manually cleaned the data up and addad a bunch of labels.
The labels are not needed because all trace array is allocated with
a kzalloc which initializes it to 0 and all kfree()s can take a NULL
pointer and will ignore it.

Adding a new helper function free_trace_buffers() that can also take
null buffers to free the buffers that were allocated by
allocate_trace_buffers().

Link: http://lkml.kernel.org/r/20140605223522.32311.31664.stgit@yunodevel



Reported-by: default avatarYoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 748ec3a2

kernel/trace/trace.c

+20 −2
Original line number Original line Diff line number Diff line
@@ -6232,6 +6232,25 @@ static int allocate_trace_buffers(struct trace_array *tr, int size) 
	return 0;

	return 0;

}

}





static void free_trace_buffers(struct trace_array *tr)

{

	if (!tr)

		return;



	if (tr->trace_buffer.buffer) {

		ring_buffer_free(tr->trace_buffer.buffer);

		tr->trace_buffer.buffer = NULL;

		free_percpu(tr->trace_buffer.data);

	}



#ifdef CONFIG_TRACER_MAX_TRACE

	if (tr->max_buffer.buffer) {

		ring_buffer_free(tr->max_buffer.buffer);

		tr->max_buffer.buffer = NULL;

	}

#endif

}



static int new_instance_create(const char *name)

static int new_instance_create(const char *name)

{

{

	struct trace_array *tr;

	struct trace_array *tr;
@@ -6290,8 +6309,7 @@ static int new_instance_create(const char *name) 
	return 0;

	return 0;





 out_free_tr:

 out_free_tr:

	if (tr->trace_buffer.buffer)

	free_trace_buffers(tr);

		ring_buffer_free(tr->trace_buffer.buffer);

	free_cpumask_var(tr->tracing_cpumask);

	free_cpumask_var(tr->tracing_cpumask);

	kfree(tr->name);

	kfree(tr->name);

	kfree(tr);

	kfree(tr);