Commit 23aaa3c1 authored Jun 06, 2014 by Steven Rostedt (Red Hat) Committed by Steven Rostedt Jun 06, 2014

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: Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

parent 748ec3a2

kernel/trace/trace.c

+20 −2

Original line number	Diff line number	Diff line
		@@ -6232,6 +6232,25 @@ static int allocate_trace_buffers(struct trace_array *tr, int size)
		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)
		{
		struct trace_array *tr;
		@@ -6290,8 +6309,7 @@ static int new_instance_create(const char *name)
		return 0;

		out_free_tr:
		if (tr->trace_buffer.buffer)
		ring_buffer_free(tr->trace_buffer.buffer);
		free_trace_buffers(tr);
		free_cpumask_var(tr->tracing_cpumask);
		kfree(tr->name);
		kfree(tr);

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