ubifs: Fix wrong memory allocation

In create_default_filesystem() when we allocate the idx node we must use
the idx_node_size we calculated just one line before, not tmp, which
contains completely other data.

Fixes: c4de6d7e ("ubifs: Refactor create_default_filesystem()")
Cc: stable@vger.kernel.org # v4.20+
Reported-by: Naga Sureshkumar Relli <nagasure@xilinx.com>
Tested-by: Naga Sureshkumar Relli <nagasure@xilinx.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>

fs/ubifs/sb.c

@@ -161,7 +161,7 @@ static int create_default_filesystem(struct ubifs_info *c)
 	sup = kzalloc(ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size), GFP_KERNEL);
 	mst = kzalloc(c->mst_node_alsz, GFP_KERNEL);
 	idx_node_size = ubifs_idx_node_sz(c, 1);
-	idx = kzalloc(ALIGN(tmp, c->min_io_size), GFP_KERNEL);
+	idx = kzalloc(ALIGN(idx_node_size, c->min_io_size), GFP_KERNEL);
 	ino = kzalloc(ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size), GFP_KERNEL);
 	cs = kzalloc(ALIGN(UBIFS_CS_NODE_SZ, c->min_io_size), GFP_KERNEL);