5880 Increase IOV_MAX to at least 1024
Portions contributed by: Jerry Jelinek <jerry.jelinek@joyent.com>

@@ -19,10 +19,11 @@
  * CDDL HEADER END
  */
 
 /*
  * Copyright (c) 1982, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright 2015, Joyent, Inc. All rights reserved.
  */
 
 /*
  * Indirect console driver for Sun.
  *

@@ -51,10 +52,11 @@
 #include <sys/taskq.h>
 #include <sys/log.h>
 #include <sys/vnode.h>
 #include <sys/uio.h>
 #include <sys/stat.h>
+#include <sys/limits.h>
 
 #include <sys/console.h>
 #include <sys/consdev.h>
 
 #include <sys/stream.h>

@@ -412,18 +414,28 @@
         /*
          * Output to virtual console for logging if enabled.
          */
         if (vsconsvp != NULL && vsconsvp->v_stream != NULL) {
                 struiod_t uiod;
+                struct iovec buf[IOV_MAX_STACK];
+                int iovlen = 0;
 
+                if (uio->uio_iovcnt > IOV_MAX_STACK) {
+                        iovlen = uio->uio_iovcnt * sizeof (iovec_t);
+                        uiod.d_iov = kmem_alloc(iovlen, KM_SLEEP);
+                } else {
+                        uiod.d_iov = buf;
+                }
+
                 /*
                  * strwrite modifies uio so need to make copy.
                  */
-                (void) uiodup(uio, &uiod.d_uio, uiod.d_iov,
-                    sizeof (uiod.d_iov) / sizeof (*uiod.d_iov));
+                (void) uiodup(uio, &uiod.d_uio, uiod.d_iov, uio->uio_iovcnt);
 
                 (void) strwrite(vsconsvp, &uiod.d_uio, cred);
+                if (iovlen != 0)
+                        kmem_free(uiod.d_iov, iovlen);
         }
 
         if (rconsvp->v_stream != NULL)
                 return (strwrite(rconsvp, uio, cred));
         else