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Subject[PATCH v2 4/7] blktrace: fix memory leak when freeing struct blk_io_trace
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: Li Zefan <lizf@cn.fujitsu.com>
---
kernel/trace/blktrace.c | 29 ++++++++++++-----------------
1 files changed, 12 insertions(+), 17 deletions(-)
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 8d6bd12..2f21d77 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -247,7 +247,7 @@ record_it:
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;
}

--
1.5.4.rc3




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