perf/qr: Use a ref-ed data to extract content

qr_content_extract used dict_get to get the value of
the GF_CONTENT_KEY key. dict_get does not ref the data
before returning it so QR could be acting on freed memory
if another thread deletes the key before then.
This patch also fixes a race in dict_get_with_ref.

Fix: Use dict_get_with_ref to retrieve the file contents.

Change-Id: Ib1a7a70bb92eed7e70747ec530e0b3edc53127ec
BUG: 1484709
Signed-off-by: N Balachandran <nbalacha@redhat.com>
Reviewed-on: https://review.gluster.org/18115
Smoke: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Amar Tumballi <amarts@redhat.com>
Tested-by: Raghavendra G <rgowdapp@redhat.com>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Raghavendra G <rgowdapp@redhat.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/xlators/performance/quick-read/src/quick-read.c b/xlators/performance/quick-read/src/quick-read.c
index 8edf495fcdd..92b2f8266ea 100644
--- a/xlators/performance/quick-read/src/quick-read.c
+++ b/xlators/performance/quick-read/src/quick-read.c
@@ -268,17 +268,19 @@ qr_content_extract (dict_t *xdata)
 	data_t  *data = NULL;
 	void    *content = NULL;
 
-	data = dict_get (xdata, GF_CONTENT_KEY);
+	dict_get_with_ref (xdata, GF_CONTENT_KEY, &data);
 	if (!data)
 		return NULL;
 
 	content = GF_CALLOC (1, data->len, gf_qr_mt_content_t);
 	if (!content)
-		return NULL;
+		goto out;
 
 	memcpy (content, data->data, data->len);
 
-	return content;
+out:
+        data_unref (data);
+        return content;
 }