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tracing: Kill the unbalanced tr->ref++ in tracing_buffers_open()

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commit e70e78e3c8 upstream.

tracing_buffers_open() does trace_array_get() and then it wrongly
inrcements tr->ref again under trace_types_lock. This means that
every caller leaks trace_array:

	# cd /sys/kernel/debug/tracing/
	# mkdir instances/X
	# true < instances/X/per_cpu/cpu0/trace_pipe_raw
	# rmdir instances/X
	rmdir: failed to remove `instances/X': Device or resource busy

Link: http://lkml.kernel.org/r/20130719153644.GA18899@redhat.com

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Oleg Nesterov 2013-07-19 17:36:44 +02:00 committed by Greg Kroah-Hartman
parent e45ccd09b5
commit e556799143
1 changed files with 0 additions and 2 deletions
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2
kernel/trace/trace.c
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@ -4907,8 +4907,6 @@ static int tracing_buffers_open(struct inode *inode, struct file *filp)
mutex_lock(&trace_types_lock);
tr->ref++;
info->iter.tr = tr;
info->iter.cpu_file = tc->cpu;
info->iter.trace = tr->current_trace;