[S390] sclp: handle empty event buffers

Handle a malformed hardware response which some versions of the
Support Element (SE) may present during SE restart and which otherwise
would result in an endless loop in function sclp_dispatch_evbufs.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/s390/char/sclp.c b/drivers/s390/char/sclp.c
index 1fd8f2193ed8..4377e93a43d7 100644
--- a/drivers/s390/char/sclp.c
+++ b/drivers/s390/char/sclp.c
@@ -280,8 +280,11 @@ sclp_dispatch_evbufs(struct sccb_header *sccb)
         rc = 0;
         for (offset = sizeof(struct sccb_header); offset < sccb->length;
              offset += evbuf->length) {
-                /* Search for event handler */
                 evbuf = (struct evbuf_header *) ((addr_t) sccb + offset);
+                /* Check for malformed hardware response */
+                if (evbuf->length == 0)
+                        break;
+                /* Search for event handler */
                 reg = NULL;
                 list_for_each(l, &sclp_reg_list) {
                         reg = list_entry(l, struct sclp_register, list);