In xbd_connect(), use correct scanf conversion specifiers for the

feature_barrier and feature_flush variables.  Otherwise, adjacent
variables on the stack, such as sector_size, may be overwritten, with
disastrous results.

Note that I did not see a good reason to revert the addition of zero
checks introduced in r310013.  Better safe than sorry.

PR:		215209
Tested by:	royger
MFC after:	3 days

diff --git a/sys/dev/xen/blkfront/blkfront.c b/sys/dev/xen/blkfront/blkfront.c
index 2e09c2eb40942fece80e90b834aacfce3e9a05c6..9eca2201f89bda0828107c69628f9c5efcaf0020 100644 (file)
--- a/sys/dev/xen/blkfront/blkfront.c
+++ b/sys/dev/xen/blkfront/blkfront.c
@@ -1259,13 +1259,13 @@ xbd_connect(struct xbd_softc *sc)
        if (err || phys_sector_size <= sector_size)
                phys_sector_size = 0;
        err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
-            "feature-barrier", "%lu", &feature_barrier,
+            "feature-barrier", "%d", &feature_barrier,
             NULL);
        if (err == 0 && feature_barrier != 0)
                sc->xbd_flags |= XBDF_BARRIER;
 
        err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
-            "feature-flush-cache", "%lu", &feature_flush,
+            "feature-flush-cache", "%d", &feature_flush,
             NULL);
        if (err == 0 && feature_flush != 0)
                sc->xbd_flags |= XBDF_FLUSH;