mtd: Do not allow MTD devices with inconsistent erase properties

Boris Brezillon · Boris Brezillon · commit 33f45c44d68b · 2018-01-06T15:09:40.000+01:00
When mtd-&gt;erasesize is 0 or mtd-&gt;_erase is NULL, that means the device
does not support the erase operation, which in turn means it should
have the MTD_NO_ERASE flag set.

Signed-off-by: Boris Brezillon &lt;boris.brezillon@free-electrons.com&gt;
Reviewed-by: Miquel Raynal &lt;miquel.raynal@free-electrons.com&gt;
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
@@ -503,6 +503,11 @@ int add_mtd_device(struct mtd_info *mtd)
 		return -EEXIST;
 
 	BUG_ON(mtd->writesize == 0);
+
+	if (WARN_ON((!mtd->erasesize || !mtd->_erase) &&
+		    !(mtd->flags & MTD_NO_ERASE)))
+		return -EINVAL;
+
 	mutex_lock(&mtd_table_mutex);
 
 	i = idr_alloc(&mtd_idr, mtd, 0, 0, GFP_KERNEL);
