Fix error paths if md_probe fails.

md_probe can fail (e.g. alloc_disk could fail) without
returning an error (as it alway returns NULL).
So when we call mddev_find immediately afterwards, we need
to check that md_probe actually succeeded.  This means checking
that mdev->gendisk is non-NULL.

cc: <stable@kernel.org>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Neil Brown <neilb@suse.de>

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 7cf512a34ccf..2580ac1b9b0f 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3897,8 +3897,10 @@ static void autorun_devices(int part)
 
                 md_probe(dev, NULL, NULL);
                 mddev = mddev_find(dev);
-                if (!mddev) {
-                        printk(KERN_ERR 
+                if (!mddev || !mddev->gendisk) {
+                        if (mddev)
+                                mddev_put(mddev);
+                        printk(KERN_ERR
                                 "md: cannot allocate memory for md drive.\n");
                         break;
                 }