mtd: Fix kernel NULL pointer dereference in physmap.c

During the probe for physmap platform flash devices there are a
number error exit conditions that all do a goto err_out which
then calls physmap_flash_remove().  In that function one of the
cleanup steps is:

#ifdef CONFIG_MTD_CONCAT
	if (info->cmtd != info->mtd[0])
		mtd_concat_destroy(info->cmtd);
#endif

This test will succeed since info->cmtd == NULL and info->mtd[0] is
valid.

Fix this by exiting the remove function when info->cmtd == NULL.

Also, cleanup the #ifdef CONFIG_MTD_PARTITIONS stuff by using
mtd_has_partitions().

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 25 insertions, 24 deletions

diff --git a/drivers/mtd/maps/physmap.c b/drivers/mtd/maps/physmap.c
index 380648e9051a..65f52d4804a2 100644
--- a/drivers/mtd/maps/physmap.c
+++ b/drivers/mtd/maps/physmap.c
@@ -44,22 +44,23 @@ static int physmap_flash_remove(struct platform_device *dev)
                 return 0;
         platform_set_drvdata(dev, NULL);
 
+        if (info->cmtd == NULL)
+                return 0;
+
         physmap_data = dev->dev.platform_data;
 
-        if (info->cmtd) {
-#ifdef CONFIG_MTD_PARTITIONS
-                if (info->nr_parts || physmap_data->nr_parts)
+        if (mtd_has_partitions()) {
+                if (info->nr_parts || physmap_data->nr_parts) {
                         del_mtd_partitions(info->cmtd);
-                else
+
+                        if (info->nr_parts)
+                                kfree(info->parts);
+                } else {
                         del_mtd_device(info->cmtd);
-#else
+                }
+        } else {
                 del_mtd_device(info->cmtd);
-#endif
         }
-#ifdef CONFIG_MTD_PARTITIONS
-        if (info->nr_parts)
-                kfree(info->parts);
-#endif
 
 #ifdef CONFIG_MTD_CONCAT
         if (info->cmtd != info->mtd[0])
@@ -169,22 +170,22 @@ static int physmap_flash_probe(struct platform_device *dev)
         if (err)
                 goto err_out;
 
-#ifdef CONFIG_MTD_PARTITIONS
-        err = parse_mtd_partitions(info->cmtd, part_probe_types,
-                                &info->parts, 0);
-        if (err > 0) {
-                add_mtd_partitions(info->cmtd, info->parts, err);
-                info->nr_parts = err;
-                return 0;
-        }
+        if (mtd_has_partitions()) {
+                err = parse_mtd_partitions(info->cmtd, part_probe_types,
+                                        &info->parts, 0);
+                if (err > 0) {
+                        add_mtd_partitions(info->cmtd, info->parts, err);
+                        info->nr_parts = err;
+                        return 0;
+                }
 
-        if (physmap_data->nr_parts) {
-                printk(KERN_NOTICE "Using physmap partition information\n");
-                add_mtd_partitions(info->cmtd, physmap_data->parts,
-                                   physmap_data->nr_parts);
-                return 0;
+                if (physmap_data->nr_parts) {
+                        printk(KERN_NOTICE "Using physmap partition information\n");
+                        add_mtd_partitions(info->cmtd, physmap_data->parts,
+                                        physmap_data->nr_parts);
+                        return 0;
+                }
         }
-#endif
 
         add_mtd_device(info->cmtd);
         return 0;