mtd: physmap: fix NULL pointer dereference in error path

commit e480814f138cd5d78a8efe397756ba6b6518fdb6 ("[MTD] [MAPS] physmap:
fix wrong free and del_mtd_{partition,device}") introduces a NULL pointer
dereference in physmap_flash_remove when called from the error path in
physmap_flash_probe (if map_probe failed).

Call del_mtd_{partition,device} only if info->cmtd was not NULL.

Reported-by: pHilipp Zabel <philipp.zabel@gmail.com>
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 8 deletions

diff --git a/drivers/mtd/maps/physmap.c b/drivers/mtd/maps/physmap.c
index 4b122e7ab4b3..229718222db7 100644
--- a/drivers/mtd/maps/physmap.c
+++ b/drivers/mtd/maps/physmap.c
@@ -46,16 +46,19 @@ static int physmap_flash_remove(struct platform_device *dev)
 
         physmap_data = dev->dev.platform_data;
 
+        if (info->cmtd) {
 #ifdef CONFIG_MTD_PARTITIONS
-        if (info->nr_parts) {
-                del_mtd_partitions(info->cmtd);
-                kfree(info->parts);
-        } else if (physmap_data->nr_parts)
-                del_mtd_partitions(info->cmtd);
-        else
-                del_mtd_device(info->cmtd);
+                if (info->nr_parts || physmap_data->nr_parts)
+                        del_mtd_partitions(info->cmtd);
+                else
+                        del_mtd_device(info->cmtd);
 #else
-        del_mtd_device(info->cmtd);
+                del_mtd_device(info->cmtd);
+#endif
+        }
+#ifdef CONFIG_MTD_PARTITIONS
+        if (info->nr_parts)
+                kfree(info->parts);
 #endif
 
 #ifdef CONFIG_MTD_CONCAT