"--export" segfaults with non-persistent super blocks

From: Tim Woods <timwoods@uklinux.net>

	This patch fixes a NULL pointer dereference in Detail.c when running
'mdadm --detail --export' on a device with non-persistent super blocks.

1 files changed, 2 insertions, 1 deletions

diff --git a/Detail.c b/Detail.c
index 7e14163..ed100fa 100644
--- a/Detail.c
+++ b/Detail.c
@@ -137,7 +137,8 @@ int Detail(char *dev, int brief, int export, int test, char *homehost)
 		printf("MD_DEVICES=%d\n", array.raid_disks);
 		printf("MD_METADATA=%d.%d\n", array.major_version,
 		       array.minor_version);
-		st->ss->export_super(super);
+		if (super)
+			st->ss->export_super(super);
 		goto out;
 	}