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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2014-11-30 13:51:03 +0100
committerBrian Norris <computersforpeace@gmail.com>2014-12-12 19:12:16 -0800
commit92b633a8a482c4bc1ff3b7cffdcace7836861554 (patch)
tree7b64321201ddde6d9cd049851039156d3221a39b /drivers/mtd/maps
parent58c81957b7d284c57a9fc1b815c77155ef744ea5 (diff)
downloadlinux-92b633a8a482c4bc1ff3b7cffdcace7836861554.tar.gz
mtd: physmap_of: fix potential NULL dereference
On device remove, when testing the cmtd field of an of_flash
struct to decide whether it is a concatenated device or not,
we get a false positive on cmtd == NULL, and dereference it
subsequently. This may occur if of_flash_remove() is called
from the cleanup path of of_flash_probe().

Instead, test for NULL first, and only then perform the test
for a concatenated device.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Diffstat (limited to 'drivers/mtd/maps')
-rw-r--r--drivers/mtd/maps/physmap_of.c8
1 files changed, 3 insertions, 5 deletions
diff --git a/drivers/mtd/maps/physmap_of.c b/drivers/mtd/maps/physmap_of.c
index c1d21cb501ca..e48930424091 100644
--- a/drivers/mtd/maps/physmap_of.c
+++ b/drivers/mtd/maps/physmap_of.c
@@ -47,14 +47,12 @@ static int of_flash_remove(struct platform_device *dev)
 		return 0;
 	dev_set_drvdata(&dev->dev, NULL);
 
-	if (info->cmtd != info->list[0].mtd) {
+	if (info->cmtd) {
 		mtd_device_unregister(info->cmtd);
-		mtd_concat_destroy(info->cmtd);
+		if (info->cmtd != info->list[0].mtd)
+			mtd_concat_destroy(info->cmtd);
 	}
 
-	if (info->cmtd)
-		mtd_device_unregister(info->cmtd);
-
 	for (i = 0; i < info->list_size; i++) {
 		if (info->list[i].mtd)
 			map_destroy(info->list[i].mtd);