1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/isdn/capi/capiutil.c b/drivers/isdn/capi/capiutil.c
index c7c29022a23a..16f2e465e5f9 100644
--- a/drivers/isdn/capi/capiutil.c
+++ b/drivers/isdn/capi/capiutil.c
@@ -989,6 +989,8 @@ _cdebbuf *capi_cmsg2str(_cmsg * cmsg)
 {
         _cdebbuf *cdb;
 
+        if (!cmsg->m)
+                return NULL;    /* no message */
         cdb = cdebbuf_alloc();
         if (!cdb)
                 return NULL;