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Commit ad5dd549 authored by Li Zefan's avatar Li Zefan Committed by Ingo Molnar
Browse files

blktrace: fix memory leak when freeing struct blk_io_trace 



Impact: fix mixed ioctl and ftrace-plugin blktrace use memory leak

When mixing the use of ioctl-based blktrace and ftrace-based blktrace,
we can leak memory in this way:

  # btrace /dev/sda > /dev/null &
  # echo 0 > /sys/block/sda/sda1/trace/enable

now we leak bt->dropped_file, bt->msg_file, bt->rchan...

Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Acked-by: default avatarJens Axboe <jens.axboe@oracle.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 17ba97e3

kernel/trace/blktrace.c

+12 −17
Original line number Diff line number Diff line
@@ -247,7 +247,7 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, 
static struct dentry *blk_tree_root;

static DEFINE_MUTEX(blk_tree_mutex);



static void blk_trace_cleanup(struct blk_trace *bt)

static void blk_trace_free(struct blk_trace *bt)

{

	debugfs_remove(bt->msg_file);

	debugfs_remove(bt->dropped_file);
@@ -255,6 +255,11 @@ static void blk_trace_cleanup(struct blk_trace *bt) 
	free_percpu(bt->sequence);

	free_percpu(bt->msg_data);

	kfree(bt);

}



static void blk_trace_cleanup(struct blk_trace *bt)

{

	blk_trace_free(bt);

	if (atomic_dec_and_test(&blk_probes_ref))

		blk_unregister_tracepoints();

}
@@ -410,11 +415,11 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 
		if (buts->name[i] == '/')

			buts->name[i] = '_';



	ret = -ENOMEM;

	bt = kzalloc(sizeof(*bt), GFP_KERNEL);

	if (!bt)

		goto err;

		return -ENOMEM;



	ret = -ENOMEM;

	bt->sequence = alloc_percpu(unsigned long);

	if (!bt->sequence)

		goto err;
@@ -483,17 +488,7 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev, 


	return 0;

err:

	if (bt) {

		if (bt->msg_file)

			debugfs_remove(bt->msg_file);

		if (bt->dropped_file)

			debugfs_remove(bt->dropped_file);

		free_percpu(bt->sequence);

		free_percpu(bt->msg_data);

		if (bt->rchan)

			relay_close(bt->rchan);

		kfree(bt);

	}

	blk_trace_free(bt);

	return ret;

}
@@ -1091,6 +1086,7 @@ static void blk_tracer_print_header(struct seq_file *m) 


static void blk_tracer_start(struct trace_array *tr)

{

	blk_tracer_enabled = true;

	trace_flags &= ~TRACE_ITER_CONTEXT_INFO;

}
@@ -1098,18 +1094,17 @@ static int blk_tracer_init(struct trace_array *tr) 
{

	blk_tr = tr;

	blk_tracer_start(tr);

	blk_tracer_enabled = true;

	return 0;

}



static void blk_tracer_stop(struct trace_array *tr)

{

	blk_tracer_enabled = false;

	trace_flags |= TRACE_ITER_CONTEXT_INFO;

}



static void blk_tracer_reset(struct trace_array *tr)

{

	blk_tracer_enabled = false;

	blk_tracer_stop(tr);

}
@@ -1250,7 +1245,7 @@ static int blk_trace_remove_queue(struct request_queue *q) 
	if (atomic_dec_and_test(&blk_probes_ref))

		blk_unregister_tracepoints();



	kfree(bt);

	blk_trace_free(bt);

	return 0;

}