mdmon: Fix crash if /proc/mdstat lists 0.9 superblocks

Signed-off-by: Michal Marek <mmarek@suse.cz>

diff --git a/mdmon.c b/mdmon.c
index 1f39f165d620035aebc06112a7ee872ceb34269b..a51a94fa9e3526481efb81323caebaf281b7bbc8 100644 (file)
--- a/mdmon.c
+++ b/mdmon.c
@@ -300,7 +300,8 @@ int main(int argc, char *argv[])
                /* launch an mdmon instance for each container found */
                mdstat = mdstat_read(0, 0);
                for (e = mdstat; e; e = e->next) {
-                       if (strncmp(e->metadata_version, "external:", 9) == 0 &&
+                       if (e->metadata_version &&
+                           strncmp(e->metadata_version, "external:", 9) == 0 &&
                            !is_subarray(&e->metadata_version[9])) {
                                devname = devnum2devname(e->devnum);
                                /* update cmdline so this mdmon instance can be