[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>

diff --git a/drivers/s390/char/sclp.c b/drivers/s390/char/sclp.c
index 1fd8f2193ed853b143cdd25d1792224c91f4f1b9..4377e93a43d7f97b7087ed5164967743337fc8a5 100644 (file)
--- 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);