libxl: Fix blktap2 for xl cset 21586:c3c2bcafe471

Avoids a double free on automatic memory.

Signed-off-by: Daniel Stodden <daniel.stodden@citrix.com>

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 87fd44d05829df17ef4b2e0c5d2e9662e45a3f1f..c502299e274739b1357f712808474f93302fc6cb 100644 (file)
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -1253,13 +1253,15 @@ static char *get_blktap2_device(struct libxl_ctx *ctx,
 static char *make_blktap2_device(struct libxl_ctx *ctx,
                                 const char *name, const char *type)
 {
-    char *params, *devname;
+    char *params, *devname = NULL, *rv = NULL;
     int err;
     params = libxl_sprintf(ctx, "%s:%s", type, name);
-    devname = NULL;
     err = tap_ctl_create(params, &devname);
-    free(params);
-    return err ? NULL : devname;
+    if (!err) {
+        rv = libxl_sprintf(ctx, devname);
+        free(devname);
+    }
+    return rv;
 }
 
 int libxl_device_disk_add(struct libxl_ctx *ctx, uint32_t domid, libxl_device_disk *disk)